Blog on ZeroSharp

Moving from Octopress to Hugo

Sat, 02 May 2026 08:00:00 +0100

I have converted this whole blog from Octopress to Hugo and modernised the theme.

I haven’t blogged in a while, and the prospect of getting Octopress to build on a modern machine had become its own deterrent. So before I could write anything, I had to do something about the platform. But I’m not sure I would ever have bothered until Claude Code made things easy.

Has the Riemann Hypothesis been proven?

Sun, 23 Sep 2018 08:35:00 +0100

Tomorrow could be an exciting moment in the history of maths. Sir Michael Atiyah is presenting a proof of the Riemann Hypothesis at the Heidelberg Laureate Forum which will be available on their youtube channel. There is a good angle by Ken Regan on the Gödel’s Lost Letter blog.

The Riemann Hypothesis is one of the most important unsolved problems in mathematics and the subject of one of my favourite books about maths: Prime Obsession.

My essential web applications and iPhone apps

Tue, 18 Sep 2018 09:27:00 +0100

This is part three of a series of posts about the software and tools I find invaluable. See Part 1: essential applications and Part 2: Visual Studio tools. In this post I’m covering the online applications and iPhone apps I find indispensable.

Gmail

Does the job.

Lastpass

Everyone needs a password manager.

Pinboard (and the PinSwift iPhone app)

The best bookmark tracking tool. Simple, fast, powerful. The best mobile app for it is PinSwift.

My essential Visual Studio tools and extensions

Mon, 10 Sep 2018 15:45:00 +0100

This is part two of a series of posts about the software and tools I find invaluable. See part 1 and part 3.

CodeRush

I’ve been using DevExpress CodeRush since 2005. Check out this video tutorial for a lightening tour of a lot of the features, and look at the DevExpress youtube channel for a load of other tutorials.

NCrunch

NCrunch provides continuous testing for Visual Studio. When I make any change to my code which breaks a unit test, the NCrunch risk status goes red a few seconds later, even without recompiling. I get immediate feedback for any breaking change, so long as I have a test for it. Not only does it encourages me and my team to write good tests, but it allows us to make new changes and refactor with confidence.

My essential applications

Fri, 07 Sep 2018 15:23:00 +0100

This is the first in a series of posts where I list the applications that I use and enjoy the most. See part 2 and part 3.

A bit of preamble, my most powerful machine is a Windows-only desktop with lots of RAM and an SSD drive. I use it almost exclusively for development.

I also have a Macbook Pro which is configured to dual-boot Windows and MacOS. The Windows machine is more or less a mirror of my main development machine. The Mac is where I do all my document editing, Word, blogging, etc. I also use it for my occasional forays in to iPhone development or other non-Windows experiments.

Macbook and the mysterious sleep

Wed, 23 Aug 2017 16:46:00 +0100

I finally worked out why my Macbook was randomly sleeping.

TL;DR - Skip to the end.

Clues

It only seemed to happen when I was working while sitting up on the bed with the computer on my lap. It seemed to be related to the position of the computer or possibly the lid. The computer would sleep. I’d wake it and login again. Continue. Sometimes it would happen once. Sometimes three times in ten minutes. Annoying. I assumed some hardware defect.

Improvements to Serverless PHP support

Thu, 02 Mar 2017 11:37:00 +0100

I was inspired by two events to jump back into serverless framework.

Firstly, I attended the second London serverless meetup yesterday evening which was excellent and showed just how much enthusiasm there is for serverless architectures. Check out their new logo on the left. It was significant that each of the three speakers announced that they are actively hiring serverless developers.

Secondly, Stolz has contributed improvements to my sample project for integrating PHP into the serverless framework. It’s the purpose of this blog post to cover the changes.

A concrete PHP Serverless example - export chess games in PDF

Tue, 29 Nov 2016 17:37:00 +0100

In the last post I built a PHP capable sample project for the Serverless Framework. In this post, I’ll show a concrete use of it.

The service I’m building connects runs a PHP function for pretty-printing chess games from the lichess online chess server. James Clarke has written a PHP function to do this using fpdf17.

The lichess exporter takes the game id of any game that has been played on the lichess server and produced a PDF output. Take for example, Game 8 of the current World Championship which is here. When I open the resulting file, I see this:

The Serverless Framework and PHP

Mon, 21 Nov 2016 09:21:00 +0100

The goal of this post is to explain how to call a PHP function from within an AWS lambda using the Serverless Framework.

Prerequisites

First check everything we need is installed.

$ serverless --version
1.1.0
$ node --version
v7.1.0

Install the sample PHP function

Install my sample Hello function from my github repository.

$ sls install --url https://github.com/ZeroSharp/serverless-php

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Serverless: Downloading and installing "serverless-php"…
Serverless: Successfully installed "serverless-php".

The code

$ cd serverless-php

Let’s have a look at the serverless.yml file.

Smart hiding of the selection boxes in XAF web applications

Sun, 06 Nov 2016 18:39:00 +0100

When an XAF list view has no selection-based actions available, the selection box still appears in the grid. Users get confused. In this post, we’ll look at a workaround.

The problem

In the XAF MainDemo, lets make Departments read-only for the User role.

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userRole.AddTypePermissionsRecursively<Department>(SecurityOperations.Create, SecurityPermissionState.Deny);
userRole.AddTypePermissionsRecursively<Department>(SecurityOperations.Write, SecurityPermissionState.Deny);
userRole.AddTypePermissionsRecursively<Department>(SecurityOperations.Delete, SecurityPermissionState.Deny);

Then start the web application, login as John and navigate to the Departments list view. There is a column selection box, but it serves no purpose. There are no actions that depend on a grid selection.

Sometimes you've just got to deploy

Sun, 16 Oct 2016 18:44:00 +0100

Sometimes the deadline has arrived and you still have some failing tests. After a discussion with the dev team, you decide to deploy anyway and fix the bugs for the next release. You need to get the build server to ignore the tests.

One way is just to mark the test with the [Ignore] attribute.

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[Test]
[Ignore] // TODO: Fix this test before the next release!
public void Test()
{
 // Some failing test code...
}

After the weekend, everyone forgets about the ignored tests and they never get fixed.

Boxstarter and checksums

Thu, 22 Sep 2016 21:04:00 +0100

I’ve blogged before about using BoxStarter to efficiently provision a new development machine.

This is working very well for our developers. Maintaining the installation script takes a bit of effort but the benefits are worth it.

Recently, the chocolatey developers have been making things more secure and recent versions now require a checksum with any downloaded package. For now, there seems to be some difficulty using Install-ChocolateyVsixPackage within BoxStarter scripts.

An XAF workaround for 'Prevent this page from creating additional dialogs.'

Mon, 16 May 2016 13:51:00 +0100

Both Chrome and Firefox have a ‘feature’ which allows a user to ignore future calls to confirm(). Once this has been checked, any subsequent calls to confirm() return false immediately without showing the window.

In XAF, this behaviour prevents the application from working correctly. For instance, it becomes impossible to confirm a deletion.

The following controller provides a work around. It injects some javascript into the page wrapping the call to confirm(). The new code detects when the Prevent this page from creating additional dialogs checkbox has been checked and returns true instead. The confirmation window still does not appear, but the XAF application works as if the user had pressed confirm instead of cancel.

A basic Chrome extension - analyze your chess.com games on lichess.org

Fri, 04 Mar 2016 17:41:00 +0100

I’ve been trying to get better at chess by playing on chess.com. I often analyse my games with the help of a computer to see where I made mistakes. My favourite way of doing this is to make use of Lichess.org’s import functionality. The latest version of chess.com has greatly improved its own post game analysis, but I still much prefer Lichess’s. So I would often download the finished game in pgn and upload it to Lichess.

Serverless Framework Part 5: Pulling in a node package

Tue, 09 Feb 2016 11:31:00 +0100

This is the final part of an ongoing series about the Serverless framework.

In the previous posts, the PasswordGenerator always returned ‘Password’. Instead each date should corresponds to a new unique password. We’ll make use of the Crypto-js node package and we’ll see that the AWS lambda copes just fine.

Installing a node package

Pull in the crypto-js package into the serverless component.

$ cd nodejscomponent/
$ npm install crypto-js --save
crypto-js@3.1.6 node_modules/crypto-js

Now we need the typescript definitions. Watch out there are two different TypeScript typings called cryptojs and crypto-js. The first one is more complete.

Serverless Framework - Part 4: Connecting the parts

Mon, 01 Feb 2016 09:44:00 +0100

This is part of an ongoing series about the Serverless framework: Part 1, part 2, part 3.

New version 0.3.1

Edit: since the original version of this post, a new version 0.3.1 of Serverless was released. I have updated the tutorial below to reflect the newer version. Also, TSD has been deprecated in favour of Typings so I’ve updated to use Typings instead. All parts have been updated for the latest version of the framework 0.3.1.

The Password of the Day Generator class

First up we need a class to generate and check the password of the day. For the moment, let’s pretend the password of the day is always the string “Password”. Put the following typescript class in nodejscomponent/src.

Serverless Framework - Part 3: The guts of a serverless service

Fri, 29 Jan 2016 17:44:00 +0100

This is part of an ongoing series about the Serverless framework. For those following along, part 1 and part 2 have been updated for the current latest version of Serverless 0.3.1.

In this post, we’ll discuss how a Serverless function actually works.

The guts of a serverless function

When we visited the deployed endpoint at the end of part 1, it correctly returned some JSON content.

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{
 message: "Your Serverless function ran successfully!"
}

Where does this message come from? Look at index.js in the component’s lib folder.

Serverless Framework - Part 2: TypeScript and Mocha

Tue, 12 Jan 2016 08:08:00 +0100

Happy New Year everyone!

This is the second part of a series about the Serverless framework. Read the first part to get up and running.

First I’ll describe the webservice I’m building. Then we’ll configure our environment for Typescript and Mocha testing.

Poor man’s dual factor authentication via a password of the day

I’m the technical lead for an enterprise application which is in use by about 100 large multinational corporates. As part of the installation process, we ask for a registration code which is based on the date. The customer has to call us to get the password of the day. This gives us an opportunity to engage with the customer and also gives us little more control. It’s a simple form of dual factor authorization where one of the factors requires a phone call.

Serverless Framework - Part 1: Up and running

Tue, 22 Dec 2015 20:26:00 +0100

New version 0.3.1

Edit: since the original version of this post, a new version 0.3.1 of Serverless was released. I have updated the tutorial below to reflect the newer version.

I was in the middle of a blog post about the JAWS framework and before I had finished it changed its name to the Serverless framework. It is a very clever way to build apps without worrying about provisioning server or whether it will scale. This is because it uses Amazon Web Services and in particular the Amazon lambda compute service. It’s currently in beta.

DevExpress 2015.2 review part 2

Thu, 10 Dec 2015 09:43:00 +0100

This is the second and final dive into some of the new DevExpress XAF 2015.2 features. The first part covers the Report Designer and the new XML serialisation.

Batch editing

Another feature I’m excited about is the support for batch editing within the web application grids.

Let’s see what happens when combined with the validation rules. What happens if I edit two rows but only one has a validation problem - does the whole batch get rejected? Or just the row with the problem?

DevExpress 2015.2 review part 1

Wed, 09 Dec 2015 14:43:00 +0100

Last week, DevExpress released 2015.2.3, their second major version of the year.

There are already some good blog posts about the changes:

Rather than repeat general overviews provided in these, this two-part blog post is more of a ‘deep dive’. In particular I’ll be looking at two of the new features in the expressApp Framework (XAF). Today I’ll cover the new XML serialisation in the report designer. Tomorrow’s post will examine the new batch editing features.

Migrating a large web application from XAF 12.1 to 15.1 - Part 3

Wed, 16 Sep 2015 09:39:00 +0100

This is the third part of a series about migrating a large application from XAF 12.1 to XAF 15.1. In this part I will compare the results of a simple stress test between the versions.

I have described in previous posts how to stress test XAF applications. One of our most basic tests is to simulate 25 users cycling through all the navigation tabs for an hour. I’m happy to report there is a considerable improvement under load in version 15.1.

Migrating a large web application from XAF 12.1 to 15.1 - Part 2

Tue, 15 Sep 2015 10:37:00 +0100

This is the second part of a series about migrating a large application from XAF 12.1 to XAF 15.1.

In the 13.1 release, DevExpress made a change to the way XAF Validator class is used. It now requires an IObjectSpace parameter corresponding to the object. It is needed to correctly evaluate any rules which are descendants of the RuleSearchObjectProperties. These include:

RuleCombinationOfPropertiesIsUnique
RuleIsReferenced
RuleObjectExists
RuleUniqueValue

A lot of our code has been around for years now and the older parts rely heavily on Session and UnitOfWork instead of IObjectSpace For the most part our application used IObjectSpace only within ViewControllers.

Migrating a large web application from XAF 12.1 to 15.1 - Part 1

Mon, 14 Sep 2015 10:01:00 +0100

I am the principal software architect for a treasury application in use by over 100 large multinational corporates. Upgrades are generally met with reluctance in the enterprise world and so we’ve been somewhat stuck on an old version of the expressAppFramework.

Recently I’ve been pushing to move to the newer version and I have spent about three weeks migrating the substantial code base to XAF 15.1 and .NET 4.6.

The steps are:

Force a complete garbage collection in an ASP.NET application.

Wed, 05 Aug 2015 09:26:00 +0100

How can I force a full garbage collection easily within an ASP.NET application? The method here is for XAF web applications but the same approach should work with any ASP.NET app.

First up: Never mess with the .NET garbage collector.

I sometimes mess with the garbage collector in .NET when I’m trying to pin down some memory problem. Also, after a load test, I prefer to force the garbage collector to collect everything it can so that I can check that the memory drops as expected.

A strange error message from Visual Studio 2015

Mon, 03 Aug 2015 15:35:00 +0100

When I recently upgraded to Visual Studio 2015, everything seemed to go very smoothly except that whenever I debugged my main application I got a dialog window with the following strange error:

The procedure entry point could not be located in the dynamic link library C:\...\bin\Debug\netutils.dll.

After pressing OK everything seemed to work as normal.

After a considerable number of dead ends, I finally worked out that changing the name of the NetUtils.dll assembly fixes the problem. It seems that Visual Studio 2015 gets confused with a Windows system assembly with the same name. I don’t know why it was never a problem with Visual Studio 2013, but I renamed the assembly and now everything is working fine.

Fixing slow debugging of ASP.NET applications

Wed, 03 Jun 2015 21:31:00 +0100

For a while I’ve noticed an annoying slowness when debugging ASP.NET applications from Visual Studio. Just after every page load it takes about a second before the buttons become clickable. I noticed mostly when debugging XAF applications, perhaps because the pages are quite complex.

Turns out the culprit is something called Browser Link which was introduced in Visual Studio 2013. It’s enabled by default.

To turn it off you can turn it off from the menu:

Top tip for viewing CSV files in Excel

Fri, 08 May 2015 11:32:00 +0100

Here’s a quick hack when your CSV file has a different separator than Excel is expecting.

Add this on the first line of the CSV file:

sep=;

sep=,

This will override system setting for list separator character and Excel will open the file correctly.

^{Note: Excel expects the separator to match the one defined in the Control Panel/Region/Formats/Additional settings/List Separator. On a French system, it expects a semi-colon.}

DevExpress 14.2 review

Tue, 20 Jan 2015 08:35:00 +0100

This post is an overview of the brand new version XAF 14.2. The truly outstanding new feature is the ASP.NET report writer which is now available in all XAF applications.

A few months ago, we lost a potential sale because the customer wanted the ability to create custom reports from within the browser. We told them it was impossible to provide a fully-fledged report designer within our web application - but the DevExpress guys have done it! And how!

ELMAH with DevExpress XAF

Wed, 08 Oct 2014 15:45:00 +0100

ELMAH (Error Logging Modules and Handlers) is an open source library for logging unhandled exceptions. This post explains how to get it running with the DevExpress XAF main demo.

A couple of amazing facts about ELMAH.

It has been around since 2004!
It was written by Atif Aziz who happens to be an old school-friend from the International School of Geneva.

XAF provides quite extensive error handling options out of the box, but I have found Elmah better suited to production environments because of the ability to remotely view the full error log.

Replacing a class at runtime using Ninject and Roslyn - Part 4: Roslyn

Wed, 17 Sep 2014 08:08:00 +0100

This is the fourth and final part of a series about using Roslyn with dependency injection to create a flexible and powerful plug-in framework. Here I review the parts of the solution that deal with the Roslyn runtime compilation of plug-ins. Check out the working example on GitHub.

Previously

Roslyn

Let’s look at some of the main classes used to compile plug-in code at runtime.

Replacing a class at runtime using Ninject and Roslyn - Part 3: Dependency Injection

Mon, 15 Sep 2014 08:01:00 +0100

This is the third part of a series about using Roslyn with dependency injection to create a flexible and powerful plug-in framework. Here I review the parts of the solution that deal with dependency injection. Check out the working example on GitHub.

Previously

Dependency injection

The first trick is to use dependency injection to create any instance of the HelloWorldGenerator class. Then if we need to add a new dependency to the class, we can just add it to the constructor without breaking anything.

Replacing a class at runtime using Ninject and Roslyn - Part 2: The Solution

Thu, 11 Sep 2014 09:18:00 +0100

Previously: Part 1: The Goal

The solution

The code for the example is available on GitHub.

How it looks

So here’s the Hello World page in production:

We navigate to the plugins view and create a new replacement for the HelloWorldGenerator:

Without restarting, we can return to the HelloWorld page and see that the new class is being used because the output has changed.

If you delete the row from the plugins page, the behaviour reverts to the original implementation (the code that was originally shipped with production).

Replacing a class at runtime using Ninject and Roslyn - Part 1: The Goal

Tue, 09 Sep 2014 10:47:00 +0100

The goal

How can we replace a given class’s code with new code at runtime? In particular, how we can we do this while allowing dependency injection and sidestepping assembly versioning issues.

Let’s say you have bunch of classes like this:

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public class SomeGenerator : IGenerator
{
 public SomeGenerator(ISomeDependency dependency, IAnotherDependency another)
 {
 ...
 }

 public void Generate()
 {
 ...
 // generate some output
 }
}

Now let’s assume that you need the ability to modify the behaviour of these classes at runtime without upgrading. And change the dependencies. Without restarting the application.

Persisting changes to config files within NuGet packages

Wed, 13 Aug 2014 06:39:00 +0100

Whenever NuGet updates or restores a NuGet package, the config files within it are overwritten. Here’s a method to make sure the changes are reapplied via a config transform whenever the solution is built.

I’m using the NUnit.Runners NuGet packages. To get our coverage tool to play nicely, I need to replace <supportedRuntime "v2.0.50727"> with <supportedRuntime "v4.0.30319"> within the NUnit-console-x86.exe.config.

Normally, a config transform is for modifying the web.config or app.config files. Here, we need to modify a config file within the packages subdirectory.

Pardon the interruption

Mon, 11 Aug 2014 10:33:00 +0100

I left my laptop on a train a couple of months ago. Good thing I remembered my brain. I’m back now. This blog still lives.

A web UI performance tip for XAF web applications

Mon, 31 Mar 2014 10:16:00 +0100

The purpose of this post is to raise your awareness of a toggle which exists in the DevExpress XAF framework which can significantly improve UI performance in the web application.

The biggest XAF project I work with has one very complex business object. The layout for this screen includes about 100 properties, several nested tabs, some custom editors, several collection properties and a whole lot of Conditional Appearance rules. It was very sluggish to navigate - it was taking several seconds to load the detail view and then it was very slow switching between tabs. Switching to edit mode was also slow.

Provisioning a new development machine with BoxStarter

Tue, 25 Feb 2014 15:29:00 +0100

I’ve been playing around with Boxstarter to configure my entire development environment with hardly any user intervention.

Here are the steps:

Install Windows 8.1 on a new machine.
Login.
Open a command prompt and enter the following.

START http://boxstarter.org/package/nr/url?http://bit.ly/1kapDXI

That’s it!

Boxstarter will self-install via ClickOnce, asking for various confirmations and ultimately it will prompt you for your login password. (This gets saved and encrypted to allow for unattended reboots and re-logins during the installation). Then the real magic begins. Boxstarter downloads and installs all your tools and configures your environment, rebooting as necessary. An hour later your full development setup is installed, including Visual Studio 2013, any VS extensions, any other programs and tools, all the browsers you need, all critical Windows updates, etc. You just saved yourself a couple of days of work and a lot of hassle.

CruiseControl Notifications on your iPhone

Fri, 07 Feb 2014 11:32:00 +0100

CCWatcher is a great iPhone app for any developer who is using CruiseControl.NET, Jenkins or Hudson for their continuous integration.

We have used CruiseControl.NET for several years to automate all builds. The build kicks off automatically whenever we push changes and this frequently happens a few times a day. We aim to have everything green at the end of every day.

A full build with unit tests and functional tests takes about an hour, so often, I will leave the office while the build is still running. But then I wouldn’t know if I’d broken the build.

Glimpse with DevExpress XAF

Tue, 17 Dec 2013 12:41:00 +0100

I have finally got around to getting Glimpse working with XAF. Glimpse is an amazing extensible ASP.NET plug-in which gives you valuable information about what is going on within your server in production. It’s also very pretty.

Let’s jump right in and have a look at what XAF looks like with Glimpse running.

That banner along the bottom of the screen is the Glimpse heads up display (HUD). Hovering over various sections of it pops up more information:

DevExpress 13.2 Review - Part 2

Tue, 10 Dec 2013 16:10:00 +0100

This is the second part of a review of the new DevExpress 13.2. In the last part we looked in-depth at the new Reports V2. In this part I’ll go over some of the other new features including the support for warnings and confirmations in the validation module.

Soft Validation Rules

With 13.2, DevExpress adds support for warning/confirmation messages to the validation engine. Warnings can be used to handle an unusual but valid data entry. An example would be:

DevExpress 13.2 Review - Part 1

Mon, 02 Dec 2013 16:23:00 +0100

The first version of XAF I ever installed was called eXpressApp-1.0.CTP2.exe in July 2006! It has certainly come a long way since then.

This post is the first part of an overview of the brand new version XAF 13.2 which will be released any day now. This part is an in-depth review of the new report writer features (still in beta).

Reports V2

Prior to this version, XAF reports were not source code. They were objects serialized to a file and then loaded into the database during initialisation. This has a lot of shortcomings some of which I have addressed in previous blog posts.

How to improve XAF grid layout for Chrome

Fri, 08 Nov 2013 09:55:00 +0100

This post proposes a workaround for a specific XAF rendering problem related to recent versions of Google Chrome.

Here is an XAF list view as it looks with IE 10 and DevExpress 13.1.8.

This is how the same view looks with Chrome 30. Notice how the column widths are rendered poorly. The minimum space is given to the string field and the date and bool fields are too wide.

Three ways to store a list of currency codes in XAF

Tue, 22 Oct 2013 18:15:00 +0100

In the last post we looked at three solutions to a relatively simple XAF requirement. In this post I’ll discuss another XAF challenge, explain the options and provide a versatile and maintainable solution.

In my DevExpress XAF application, I have an object which has several properties like this:

In each case, the field is a comma-separated list of currency codes. These fields are not very important to the model - they are used mainly for reporting.

The Ugly, the Heavy and the Good: 3 solutions to an XAF layout problem

Mon, 14 Oct 2013 09:51:00 +0100

This post aims to look at various solutions to a seemingly simple layout change.

With DevExpress XAF, a lot of the difficult things are easy: authentication, authorisation, ORM, reporting, complex form layouts, themes, etc., are all made easy by XAF. On the other hand, some of the easy things are hard. It can be frustratingly difficult to make a small modification to the basic layout. We will look at an example of such a change and evaluate the recommended DevExpress approaches.

A review of NDepend 5

Wed, 02 Oct 2013 17:54:00 +0100

NDepend is a commercial static analysis tool for .NET managed code. It’s been around a long time (since 2004!). Version 5 was just released and in this post I’m going to try it out on the DevExpress MainDemo.

In the past I have always thought of NDepend as a complex tool. I was never sure where to start. In version 5, a lot of work has been done to improve the learning curve. The installation process is easy and a wizard very quickly points you in the right direction.

Always run Visual Studio as an Administrator

Mon, 09 Sep 2013 07:49:00 +0100

I always run Visual Studio as an administrator. There are various reasons why this is necessary including:

using IIS with a web application
running web UI tests
profiling

In fact there’s a list on MSDN of all the actions you require administrator permissions.

Here is a way to make sure Visual Studio always opens with elevated privileges, even if you double click on a .sln file. (I’m running Windows 8.)

Right-click devenv.exe
Select Troubleshoot program
Check The program requires additional permissions
Click Next
Click Test the program…
Wait for the program to launch
Click Next
Select Yes, save these settings for this program
Click Close

If you have multiple versions of Visual Studio installed, you should repeat the operation for all of the following.

Fix Visual Studio update links when running as Administrator

Mon, 02 Sep 2013 09:58:00 +0100

This post is about fixing an annoyance whereby Visual Studio refuses to update extensions when running as an administrator.

I always had a problem when an update to an extension or tool tried to open the browser. For instance, I would see this notification in the system tray.

And then when I went to Tools/Extensions and Updates… in Visual Studio, I’d get to something like this:

But the Update button was not responding to any clicks. The only workaround I found was to restart Visual Studio under my normal user account and then the button would work.

MiniProfiler with DevExpress XAF

Tue, 27 Aug 2013 09:14:00 +0100

In this post I will demonstrate how to add MiniProfiler to the XAF MainDemo web application.

MiniProfiler is a simple fast profiler with a pretty user interface. It is fast because it only profiles code that you have explicitly decorated with the MiniProfiler.Step() method. It was designed by the team at StackOverflow.

First, add the MiniProfiler NuGet package to the MainDemo.Web project. Then add a placeholder to default.aspx just before the last <body> tag.

Fluent queries with DevExpress XPO - Implementation

Wed, 14 Aug 2013 11:03:00 +0100

Continuing from my last post, I’ll demonstrate how to create a fluent interface so that you can do:

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var customer = Session
 .Query()
 .InTransaction
 .Contacts
 .ByPosition("Developer")
 .ThatHave
 .NoPhoto()
 .And
 .TasksInProgress()
 .And
 .TasksWith(Priority.High) 
 .FirstOrDefault();

First, let’s look at the ‘beginning’ of the fluent interface: the Query() extension method.

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public static class QueryExtensions
{
 public static IQueries Query(this Session session)
 {
 return new Queries(session);
 }

 // If we're using XAF, do the same for ObjectSpace as well
 public static IQueries Query(this IObjectSpace objectSpace)
 {
 var xpObjectSpace = objectSpace as XPObjectSpace;
 var session = xpObjectSpace.Session;
 return new Queries(session);
 }
}

What does the Queries() class look like?

Fluent queries with DevExpress XPO - Intro

Mon, 12 Aug 2013 17:54:00 +0100

There are many ways to perform queries with XPO.

You can do this:

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 Session.FindObject<Contact>(new BinaryOperator("Name", "Elvis"));

or this

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 Session.FindObject<Contact>(CriteriaOperator.Parse("Name = 'Elvis'"));

Another way to use the simplified criteria syntax, and with the Xpo_EasyFields CodeRush plugin. Then you can do:

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Session.FindObject<Contact>(Customer.Fields.Name == "Elvis");

For each of the above, you can optionally query within the transaction by passing in the PersistentCriteriaEvaluationBehavior.InTransaction parameter.

Or we can use LINQ via XPQuery<T>.TransformExpression().

Session.FindObject<Contact>(
 XPQuery<Contact>.TransformExpression(Session, c => c.Name == "Elvis")
 );

All of these methods are powerful, but the power comes at a cost. The syntax is neither elegant nor particularly clear and as a result it is not very practical to maintain or test.

Removing the RSS subscription icon from Octopress

Tue, 09 Jul 2013 09:13:00 +0100

A fellow Octopress blogger recently asked how I removed the RSS subscription icon from the Octopress navigation bar.

First, create a new site variable show_feeds by adding a line to the _config.yml file which is in the root folder of the Octopress source.

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# _config.yml
 # RSS / Email (optional) subscription links (change if using something like Feedburner)
+ show_feeds: false
 subscribe_rss: http://feeds.feedburner.com/zerosharp
 subscribe_email:
 # RSS feeds can list your email address if you like
 email:

Then modify the source/_includes/navigation.html as follows

Making XAF reports even better - Part 2

Tue, 28 May 2013 11:51:00 +0100

Good news. The conversion is now two-way. Get the source code from GitHub. Make sure you have built MainDemo.Reports project.

You will find there are now two T4 transforms in the project. RepxToCSharp.tt is covered in the Part 1. It searches for any .repx files in the solution and converts the scripts into compilable C#.

The second transform is new. CSharpToRepx.tt copies any changes to the script part back into the original .repx files. Again, there are performance optimisations via checksums to prevent overwriting unchanged files.

Making XAF reports even better - Part 1

Tue, 21 May 2013 14:38:00 +0100

The ability to create reports using a report writer is a very powerful feature of DevExpress XAF, but there are some limitations which are particularly cumbersome to deal with in complex project.

One of the projects I work on has over 100 reports in it. Even though we make use of unit tests to ensure they are not broken, the maintenance of the code in the embedded scripts is particularly difficult to manage.

Fixing an unmanaged code AppCrash

Mon, 29 Apr 2013 16:21:00 +0100

This post is the result of a recent bug hunt in which I came across a tricky bug, found a debugging switch I’d completely forgotten existed and learned a little about calling extern string functions from C#.

I love bug hunting. It’s like a murder mystery: you’ve got your suspects and you try to eliminate them one at a time until, as a famous bug hunter said:

… when you have eliminated the impossible, whatever remains, however improbable, must be the truth.

Load Testing XAF: Bonus - Simultaneous EasyTests

Mon, 22 Apr 2013 16:31:00 +0100

In my recent series on load testing XAF, I used a Selenium javascript test to run the client browser instances. This is a good and cheap method of validating the performance of XAF applications under production load.

However, if the load tests fail because of a concurrency bug or a performance bottleneck, it can still be difficult to analyse and solve. For this, we need to be able to simulate load locally against the development environment.

Load Testing XAF: Part 5 - Analysis

Sun, 14 Apr 2013 07:37:00 +0100

This is the final post in a series about load testing XAF applications. Previously in the series:

In this part, we analyse the results of the load test we ran in Part 4.

Results

The results of the test we ran are here. The graphs are interactive and give quite interesting data about the load tests. Feel free to have a look and play around with the results.

Load Testing XAF: Part 4 - Launching the load test

Mon, 08 Apr 2013 11:19:00 +0100

This is another post in a series about load testing XAF applications. Previously in the series:

In this part, we will launch a 1 hour test with 25 virtual users using the NeuStar Web Performance Management module.

Schedule and launch a test

From the script validation screen, click on Schedule a load test with this script. The defaults are good, but you can specify in detail how to run your load test. For instance, you can coordinate multiple Selenium scripts to simulate different types of activity on your site.

Load Testing XAF: Part 3 - Uploading and Validating the Virtual User Script

Wed, 03 Apr 2013 16:39:00 +0100

This is another post in a series about load testing XAF applications. Previously in the series:

In this part, we will load test the application we set up in Part 1, using the Selenium load test we created in Part 2.

Neustar Web Performance Management

NeuStar (formerly BrowserMob) are a company specialised in web application performance monitoring. We are interested in their web performance module. It is free to create an account. To run a test with less than 25 virtual users costs only $0.15 per virtual user. Tests with more than 25 users (up to 5000) require an additional paid plan.

Load Testing XAF: Part 2 - Selenium

Thu, 28 Mar 2013 16:56:00 +0100

Writing a Selenium User Test against MainDemo

This is another post in a series about load testing XAF applications. Previously in the series:

Why not use DevExpress EasyTests?

The DevExpress recommended method of writing functional tests is to use the EasyTest functionality of the expressAppFramework. This has several advantages over other functional testing approaches.

It uses a domain specific language tailored for XAF making it easy to test views and actions
It makes it easy to interact with the DevExpress controls that are used within XAF
A single EasyTest can be run against both the ASP.NET and WinForms applications
EasyTests work against both the debug webserver and IIS

However, one feature which is not (yet) available is the ability to use EasyTests for load testing.

Load Testing XAF: Part 1 - Deploying

Fri, 22 Mar 2013 11:21:00 +0100

This is the first part of a tutorial about load testing XAF applications. See the overview for a bit of background. In this post we set up the target webserver.

You can target any machine which has a publicly available web address, but for this tutorial, I’m’ deploying the MainDemo to the Amazon cloud, by following the instructions in Part 1 and Part 2 of my previous series about Amazon Web Services.

I am using version 12.2.7 of the DevExpress XAF MainDemo. There are a couple of extra changes to make to the web.config.

Load Testing XAF: Overview

Tue, 12 Mar 2013 18:20:00 +0100

Over the next few posts, I will demonstrate how to load test XAF web applications.

History

Performance testing has traditionally been difficult and expensive. A few years ago, to do it well required a powerful piece of dedicated load testing software such as HP LoadRunner (typical cost back in 2007: USD 50,000-100,000 or more per year!). This software was capable of simulating multiple virtual users via the use of recorded scripts and providing detailed performance statistics. Usually the cost was increased further increased by the need for powerful hardware to be able to run the application.

How to recursively change file ownership

Thu, 28 Feb 2013 17:40:00 +0100

I recently ran into some file ownership trouble after cloning a bitbucket repository.

The following script saved my bacon.

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# FixOwnership.ps1
# This script recursively fixes the ownership on the files in the 
# current and subdirectories.

$acct1 = New-Object System.Security.Principal.NTAccount('Administrators')
$profilefolder = Get-Item .
$acl1 = $profilefolder.GetAccessControl()
$acl1.SetOwner($acct1)
dir -r . | set-acl -aclobject $acl1
pause

Colourful git command line

Thu, 14 Feb 2013 05:10:00 +0100

For Valentine’s Day, why not make your git command line a little more colourful.

git config --global color.ui true

A C# Developer's Adventures in iOS - Integrating Git and MonoDevelop

Fri, 08 Feb 2013 14:52:00 +0100

This is the second post in a series about iOS development from the perspective of a C# developer.

In the previous post in the series we got started with MonoTouch and installed MonoDevelop and XCode. In this post, we’ll look at how to set up version control for an existing MonoTouch solution.

Version Control

I didn’t have enough time at the hackathon to learn how to set up version control for MonoDevelop on a Mac. So let’s fix that straight away.

Clone your Octopress to blog from two places

Fri, 01 Feb 2013 11:59:00 +0100

This post covers how recreate a local repository of your Octopress blog. Perhaps you’ve accidentally lost it, or perhaps you would like to be able to blog from two different places. Recently I bought a new computer and I wanted to be able to blog from both my desktop and my laptop.

How Octopress works

Octopress repositories have two branches, source and master. The source branch contains the files that are used to generate the blog and the master contains the blog itself.

Installing Ruby with Homebrew and rbenv on Mac OS X Mountain Lion

Thu, 31 Jan 2013 17:38:00 +0100

Install Ruby with rbenv

I decided to setup Octopress on my Mac so that I can publish blog posts from either Windows or MacOS. I’m on OS X 10.8.2.

I tried to follow the Octopress instructions for installing Ruby but ran into a few problems.

Install Homebrew

Homebrew is a package manager for OS X. Open Terminal and install Homebrew with:

$ ruby -e "$(curl -fsSkL raw.github.com/mxcl/homebrew/go)"

Once the installation is successful, you can run the following command to check your environment.

A C# Developer's Adventures in iOS - Getting Started

Wed, 30 Jan 2013 11:18:00 +0100

First steps in iPhone development

This is the first in a series of posts about developing an iOS application from the perspective of a Windows C# developer.

Startup Weekend

On a recent month-long trip to South America, I took part in the Buenos Aires Startup Weekend hackathon and my team came second!](/how-i-went-from-c-number-developer-to-iphone-developer-in-a-weekend). The application we built is a treasure hunt game for tourists which helps them discover Buenos Aires. At the beginning of the weekend I knew nothing about mobile development. It was the first time I developed software using a Mac.

My amateur git skills have lead to an RSS deluge

Tue, 29 Jan 2013 11:31:00 +0100

I was trying to upgrade to the latest Octopress version but it seems I did something with the atom.xml file and some of you got every single post as ’new’ in your RSS readers. Not sure what I did, but sorry for any extra mouse clicks. All working now.

Facebook Graph Search pwns your privacy

Thu, 24 Jan 2013 11:10:00 +0100

Facebook’s new Graph Search allows you to easily see anybody’s photos.

First, search for someone who is not a friend. Most often, if you navigate to their photos, you see something like this:

You can’t see any photos because their privacy settings are not set to ‘Public’. It’s what you’d expect.

Use Graph Search to bypass privacy

If you put Photos of <name> or Photos by <name> into the new Facebook graph search you can view all their photos regardless of their privacy settings. This works even for friends who have put you on a ’limited’ profile.

Image captions for Octopress

Wed, 23 Jan 2013 11:56:00 +0100

I wanted to add captions to some of my images and came across this forum thread, from which I was able to piece together Ted Kulp’s slick solution.

The following markdown

 <figure>

Leonhard Euler

will render like this.

Leonhard Euler

It works with left and right too.

The changes

First, create the image_caption_tag plugin and put it in the plugins subfolder.

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# plugins/image_caption_tag.rb

# Title: Image tag with caption for Jekyll
# Description: Easily output images with captions

module Jekyll

 class CaptionImageTag < Liquid::Tag
 @img = nil
 @title = nil
 @class = ''
 @width = ''
 @height = ''

 def initialize(tag_name, markup, tokens)
 if markup =~ /(\S.*\s+)?(https?:\/\/|\/)(\S+)(\s+\d+\s+\d+)?(\s+.+)?/i
 @class = $1 || ''
 @img = $2 + $3
 if $5
 @title = $5.strip
 end
 if $4 =~ /\s*(\d+)\s+(\d+)/
 @width = $1
 @height = $2
 end
 end
 super
 end

 def render(context)
 output = super
 if @img
 "<span class='#{('caption-wrapper ' + @class).rstrip}'>" +
 "<img class='caption' src='#{@img}' width='#{@width}' height='#{@height}' title='#{@title}'>" +
 "<span class='caption-text'>#{@title}</span>" +
 "</span>"
 else
 "Error processing input, expected syntax: ![name(s)] /url/to/image [width height] [title text]]([class)"
 end
 end
 end
end

Liquid::Template.register_tag('imgcap', Jekyll::CaptionImageTag)

Next, modify the _utilities.scss file as follows.

Setting up Octopress on Windows Again

Thu, 17 Jan 2013 11:20:00 +0100

My very first blog post was about setting up Octopress. The following is an updated version of those instructions for setting up Octopress with Windows, ruby 1.9.3, python 2.7.3.

This is quick guide to setting up Octopress to publish to GitHub pages. I’m using Windows 8 64-bit, but the instructions should work with other versions of Windows.

Get with GitHub

First, get an account on GitHub and follow the excellent instructions for Windows here. here.

Better handling of Decimals in the XAF audit trail

Tue, 15 Jan 2013 10:29:00 +0100

The following screenshot shows the detail view of an object change from the DevExpress XAF Audit Trail. The DecimalValue property was changed from 123.45 to 543.22.

Why is the OldValue property is displayed with two trailing zeros? The corresponding property is defined as follows:

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[DefaultClassOptions]
public class MyClass : XPObject
{
 public MyClass(Session session)
 : base(session)
 { }

 //...

 private decimal _DecimalValue;
 [ModelDefault("DisplayFormat", "{0:n2}")]
 public decimal DecimalValue
 {
 get
 {
 return _DecimalValue;
 }
 set
 {
 SetPropertyValue("DecimalValue", ref _DecimalValue, value);
 }
 }

 private XPCollection<AuditDataItemPersistent> _ChangeHistory;
 public XPCollection<AuditDataItemPersistent> ChangeHistory
 {
 get
 {
 if (_ChangeHistory == null)
 {
 _ChangeHistory = AuditedObjectWeakReference.GetAuditTrail(Session, this);
 }
 return _ChangeHistory;
 }
 }
}

Explanation and fix

A C# decimal is a type which represents a number’s value and its precision. It actually stores the number of trailing zeros along with the value. For the NewValue, it has stored the decimal value as the user entered it - with no trailing zeros. Howevever, for the OldValue, it has retrieved the value from the database and used the SQL column definition to determine the precision.

How to remove the trailing zeros of precision from a C# Decimal

Wed, 09 Jan 2013 17:45:00 +0100

You may know that the C# Decimal type remembers any trailing zeros. So for instance:

Console.WriteLine(123.45m);
Console.WriteLine(123.45000m);
Console.WriteLine(123.4500000m);

results in

123.45
123.45000
123.4500000

This is because the Decimal type is designed for representing a number including its accuracy.

It is tricky to find a good way of controlling this accuracy. If I have x = 123.45000, how can I easily remove the trailing zeros so that x.ToString() outputs 123.45?

How I went from C# Developer to iPhone Developer in a Weekend

Fri, 04 Jan 2013 10:35:00 +0100

Recently I took part in Startup Weekend Buenos Aires. It works just like most hackathons:

[

New friends: Caro, Eze, Gus and me

](http://buenosaires.startupweekend.org/2012/11/12/ganadores-swba2012/)

You give a one minute pitch on Friday evening.
Winners put together a team.
You work with your team on Saturday and Sunday to launch a product.
Demo for the judges.
Prizes. Beer. Sleep.

On the Friday I spoke no Spanish and had no idea how to write an iPhone app. By Sunday I still spoke no Spanish, but I’d built my first app and it won second prize!

Deploy XAF ASP.NET Applications to Amazon Web Services: Part 5

Wed, 05 Dec 2012 11:03:00 +0100

Part 5: Load balancing

This is the final post in this 5 part series about deploying XAF to the Amazon cloud. The other parts are:

This part covers load balancing and autoscaling.

Load balancing

In order to enable load balancing with DevExpress XAF applications, you must activate client affinity (sticky sessions) which you can do in the Load Balancer tab.

Deploy XAF ASP.NET Applications to Amazon Web Services: Part 4

Mon, 05 Nov 2012 14:16:00 +0100

Part 4: Incremental Deployment

This is the fourth post in a series about deploying ASP.NET applications to the Amazon cloud. In the first three posts covered deploying the XAF ASP.NET MainDemo to the Amazon cloud (Part 1, Part 2, Part 3).

When we deployed to the Elastic Beanstalk in Part 2, we chose not to enable incremental deployment.

I want to explain this decision further.

If you choose not to deploy incrementally your deployment will take longer because the entire web deployment package needs to be uploaded every time you re-publish which takes about 4-5 minutes on my connection. The incremental deployment option creates a git repository in the target environment so that only the modified files are re-deployed. If you are frequently making changes and redploying, you can save considerable time. A re-deployment takes only a few seconds.

Deploy XAF ASP.NET Applications to Amazon Web Services: Part 3

Fri, 02 Nov 2012 17:54:00 +0100

Part 3: Troubleshooting

This is the third post in a series about deploying ASP.NET applications to the Amazon cloud.

In Part 1 we created an Amazon RDS instance of SQL Server to act as the database for the deployment.

In Part 2 we published the DevExpress MainDemo.Web to the Amazon Elastic Beanstalk.

In this part we will look at troubleshooting methods and in particular how to connect to an EC2 instance in order to troubleshoot installations.

Deploy XAF ASP.NET Applications to Amazon Web Services: Part 2

Wed, 31 Oct 2012 12:52:00 +0100

Part 2: Publishing MainDemo

This is the second post in a series about deploying ASP.NET applications to the Amazon cloud.

In Part 1 we created an Amazon RDS instance of SQL Server to act as the database for the deployment. Make sure this is up and running before continuing.

This part guides you through publishing the DevExpress XAF MainDemo application to the Amazon Elastic Beanstalk.

Amazon Elastic Beanstalk

Amazon Elastic Beanstalk provides automatic capacity provisioning, load balancing, auto-scaling, and application health monitoring. That sounds like a lot of features we don’t really need for the MainDemo, so let me explain.

Deploy XAF ASP.NET Applications to Amazon Web Services: Part 1

Tue, 23 Oct 2012 12:52:00 +0100

Part 1: Putting the Database in the Cloud

This is the first part of a tutorial for installing the DevExpress MainDemo.Web to Amazon Web Services, but the same principles apply to any ASP.NET web application.

This part covers creating an Amazon RDS instance running SQL Server Express and connecting a (locally running) MainDemo to it.

At the time of writing the DevExpress version is 12.1.7.

Amazon Web Services

If you have not already done so, you will need to sign up with Amazon Web Services. There are costs associated with AWS, but the tutorial only uses very small cheap instances which cost as little as 2 cents per hour to run. Also, new customers get a load of hours for free as part of the AWS Free Usage Tier. See the AWS pricing for more information. Don’t forget to terminate your instances when you have finished.

Incompatible character encodings when generating Octopress

Mon, 15 Oct 2012 16:26:00 +0100

I started getting an encoding error whenever I tried to generate my Octopress blog with rake generate. The error message was:

Liquid error: incompatible character encodings: UTF-8 and IBM437

I tried to save all my recently modified files with UTF-8 encoding, but I couldn’t get the error to go away until I found a solution on this blog in Chinese.

Set two environment variables (via Control Panel/System/Advanced System Settings/Environment Variables) as follows:

The best PC laptop is a Mac

Tue, 09 Oct 2012 17:09:00 +0100

A month ago

I’ve never liked laptops. The screen seems so small. A powerful laptop is too heavy; a light one doesn’t cut the mustard. I can’t even find the on/off switch.

Then there are those fancy new Macbook Pros with retina displays. They seem light and powerful and the screen looks great. I don’t know much about Macs, but I’d like to learn.

But I need Microsoft Windows and Visual Studio. I know theoretically I can run a virtual machine or setup a dual boot, but I’ll bet it’s all a bit of a hassle and rather clunky…

A look at the DevExpress MainDemo with Google Page Speed

Wed, 12 Sep 2012 17:22:00 +0100

In this post I’ll demonstrate how to use the Google Page Speed tools to analyse the performance of the DevExpress XAF MainDemo.

The easiest way to run Google Page Speed is as a Chrome or Firefox plugin. Both are available here. I use Chrome.

Now open the DevExpress MainDemo from Visual Studio. By default it is installed to:

C:\Users\Public\Documents\DXperience 12.1 Demos\eXpressApp Framework\MainDemo\CS\MainDemo.sln

Set the MainDemo.Web as the startup project and change the connection string in web.config if necessary. Launch the application with Chrome and login as ‘Sam’ (password is blank). Then press F12 to bring up the developer tools. The last tab is the Page Speed Analysis and your browser should look like this:

XpoBatch source code available

Wed, 25 Jul 2012 16:24:00 +0100

The source code for the fast batch operations with DevExpress XPO is now available on on GitHub.

It includes unit tests that can be run against SQL Server or in memory. It runs against DevExpress 12.1.7, but it will work against 11.2 (and possibly earlier versions) with a couple of minor modifications which are documented in the code.

References

Fast batch modifications with DevExpress XPO

Tue, 24 Jul 2012 14:02:00 +0100

Last week I wrote about fast batch deletions. In this post I’ll show how to do the same for modifications.

Let’s assume we want to replace the ‘State’ property with ‘CA’ and CostCenter with 123 for all records where the ‘City’ is ‘San Francisco’. The recommended DevExpress approach would be something like the following:

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using (UnitOfWork uow = new UnitOfWork())
{	
	var xpCollection = new XPCollection<MyObject>(uow, CriteriaOperator.Parse("City == 'San Francisco'"));
 foreach (MyObject myObject in xpCollection)
 {
 myObject.State = "CA";
 myObject.CostCenter = 123;
 }
 uow.CommitChanges();
}

The problem with the above code is that every record must be loaded and then an individual UPDATE command is generated for each modification. This is necessary for the business logic to be applied correctly (such as the code in methods such as OnSaving()). It is also necessary to handle record locking.

Fast batch deletions with DevExpress XPO

Thu, 12 Jul 2012 17:00:00 +0100

When deleting a collection of objects, DevExpress recommends using Session.Delete(ICollection objects). This has the same effect as calling the Delete() method for every object in the collection so that the business logic is applied correctly. The business logic in this context refers to code such as that in the OnDeleting(), OnDeleted() methods, but it also includes the clearing of references to the object by other objects. This approach is slow, but ensures the integrity of the data.

Trying out a new keyboard with no labels on the keys

Mon, 02 Jul 2012 09:35:00 +0100

My new ~~keyboarf~~ keyboard has no labels on the keys!

On a normal keyboard, I can type at about 60 wpm, but I only use three or four fingers and I have to periodically glance down at the keyboard. I hope my new keyboard forces me to learn to touch type properly. Various coders have written on the subject - Jeff Atwood says we are typists first; Phil Haack opts for Dvorak.

An afternoon with two Fields Medallists

Tue, 05 Jun 2012 08:30:00 +0100

On Saturday I attended an excellent discussion at the Tate modern which was part of a series of lectures on Topology. The first part was a screening of Au Bonheur des Maths, a film by Raymond Depardon and Claudine Nougaret which is a collection of portraits of famous mathematicians describing beauty in mathematics. The second part was a discussion on the same topic between Sir Michael Atiyah and Cédric Villani, both winners of the Fields Medal. You can read a review of the event at Tony Mann’s maths blog.

The only robot on any other planet

Wed, 30 May 2012 08:44:00 +0100

This post is part of an ongoing series about robots, past and present. See Musical Interlude.

The Mars Opportunity Rover

Opportunity landed on Mars in January 2004. It is currently the only active robot on any planet other than Earth (until the scheduled arrival of Curiosity in August 2012). The mission was originally supposed to last 90 days.

The rover contains pieces of the fallen World Trade Center which were turned into shields to protect cabling.

NuGet 1.8 Installation Problem

Fri, 25 May 2012 00:26:00 +0100

The NuGet team just released NuGet 1.8. Unfortunately there is an issue when upgrading it via the NuGet package manager. The following message appears and the installation fails.

VSIXInstaller.SignatureMismatchException: The installed version of 'NuGet Package Manager' 
is signed, but the update version has an invalid signature. Therefore, Extension Manager 
cannot install the update. 

 at VSIXInstaller.Common.VerifyMatchingExtensionSignatures(IInstalledExtension installedExtension, 
 IInstallableExtension updateExtension) 
 at VSIXInstaller.InstallProgressPage.BeginInstallVSIX(SupportedVSSKU targetAppID)

As explained in the NuGet release notes, one solution is to uninstall NuGet from the VS Extension Gallery before reinstalling. Note: If Visual Studio won’t allow you to uninstall the extension (the Uninstall button is disabled), then you likely need to restart Visual Studio using “Run as Administrator.”

Testing the property signatures of DevExpress validation rules using NUnit and LINQ

Thu, 24 May 2012 16:39:00 +0100

One of the projects I work on uses the validation module of the eXpressApp Framework (XAF). Since the business logic is complex, there are many validation rules defined using the [RuleFromBoolProperty].

One of the recurring problems occurs when the signature of the associated property is incorrect. Consider the following:

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[RuleFromBoolProperty("Invoice_IsAmountGreaterThanZero", 
 DefaultContexts.Save, 
 "Invoice amount must be greater than zero.", 
 UsedProperties = "Amount")]
public bool IsAmountGreaterThanZero
{
 get
 {
 return Amount > 0;
 }
}

Notice that the rule is declared public. This causes the getter to be executed when it is not required (see the note in the documentation). However another problem is that the default behaviour for public properties of XPObjects is to persist them to the datastore which means the application will attempt to create a new column called IsAmountGreaterThanZero.

Musical Interlude

Tue, 15 May 2012 11:10:00 +0100

This post is part of an ongoing series about robots, past and present. See Robot Egyptologists.

Robot quadcopters playing the James Bond theme tune.

There is no human controlling the robots. Each one has been assigned a series of points in space that it must reach at specific times. The robots are aware of each other and avoid collisions.

Robot Egyptologists

Tue, 01 May 2012 11:52:00 +0100

This post is part of an ongoing series about robots, past and present. See Skiing on Mars.

Mysterious Shafts in the Great Pyramid of Giza

Various robots have been used to explore secret tunnels in the Great Pyramid of Giza.

The tunnels were discovered in 1872 by Waynman Dixon, a British engineer who was helping with a project to undertake accurate measurements of the pyramid. He noticed a crack in the southern wall of the Queen’s Chamber and discovered a shaft hidden behind the masonry, as well as a similar shaft in the northern wall. The shafts are very narrow (20x14cm) and so there was no feasible method of exploring them until recently. The shafts in question are shown in red on the diagram above. There are two similar shafts in the King’s Chamber above it, but these have exits on the outside of the pyramid.

Skiing on Mars

Fri, 27 Apr 2012 11:45:00 +0100

This post is part of an ongoing series about robots, past and present. See Friends, Robots, Countrymen.

The Soviet PrOP-M Rovers

In May 1971, the USSR launched two rovers to explore Mars. They were to move on skis (!!) while connected to the landers with 15m umbilical cables.

The first one crash landed. The second landed successfully but failed twenty seconds after landing and never moved. The reasons are unknown although the landing took place in the middle of a dust storm. The base module did manage to transmit about 20 seconds worth of the first ever photograph of the surface of Mars, shown on the left here. According to the Soviet Academy of Sciences there is nothing, horizon or otherwise, identifiable in this photograph.

Friends, Robots, Countrymen

Tue, 24 Apr 2012 15:55:00 +0100

This is the first in a series of posts about robots, past and present.

Since at least the 1950s, people have claimed that we are just around the corner from a robot revolution. Perhaps it’s finally here! The robots are coming!

Recently there have been substantial advances in many different overlapping domains: the driverless car, unmanned drones, machine vision, machine translation, machine learning, speech recognition, facial recognition, swarm robotics, self-reconfiguring modular robots, powered exoskeletons, nanotechnology, etc.

Octopress on Windows and GitHub

Fri, 06 Apr 2012 17:11:00 +0100

There is a more recent version of this post which covers ruby 1.9.3, python 2.7.3.

— January 2013 update: http://blog.zerosharp.com/setting-up-octopress-on-windows-again Setting up Octopress on Windows again

---

This is quick guide to setting up [Octopress](http://octopress.org/) on a Windows 7 machine to publish to GitHub pages. It relies on ruby 1.9.2 and python 2.7.2.

Get with GitHub

First, get an account on GitHub and follow the excellent instructions for Windows here. here.