Tag Archives: practises

XAML guidelines: interviews of WPF masters

Getting back to work this morning, I opened my Google Reader to have a look at the RSS feeds I’m reading.

I found a nice video on Channel9: “XAML Guidelines, Part 2”. The first episode, where Jaime Rodriguez interviews 3 people from Identity Mines is also available on Channel9 (unfortunately, the sound is rather poor on this episode…).

This time, Jaime meets up with Unni Ravindranathan from the Expression Blend team. During the shot, they open the Blend source code project inside Blend (sounds nice isn’t it :p). Unni explains the structure of the project, their conventions, how resources are used, etc.

I think Blend is an application we can learn a lot from. If you’re also interested to understand what architecture Blend uses, you can check out this post from Paul Stovell.

Here are some notes I took while watching the video:

  • Blend is shipped with 2 themes: Expression Light & Expression Dark
  • Blend resources are stored in (only !) 3 resources dictionaries
  • Resources are categorized into Colors, Brushes and Styles
  • Blend defines a set of margins and thicknesses that are used in the entire application to ensure a consistency across the different layouts
  • By convention, Name and Key properties are always defined first in the XAML
  • Properties might be spitted over several lines, if this is the case; properties are grouped together by types (style, size, appearance…)
  • Blend 3 will add extensibility and improve XAML code generation:
      – Name will always be the first property
      – Better control over how the XAML is formatted
  • Name everything versus name nothing? Blend names almost everything, it helps UI automation
  • Static resources versus dynamic resources? No big performance impact, Blend mostly uses dynamic resources
  • When design time doesn’t work fine in Blend
      – An exception can occur when Blend is creating the control because the running process is Blend itself and not the application we are creating
      – Add tests to check if code is running in design mode (you can use System.ComponentModel.DesignerProperties.GetIsInDesignMode(DependencyObject) method)
      – Debug Blend process by attaching an instance of Visual Studio to Blend
  • Blend is a big application:
      – 300 000 lines of XAML
      – 500 000 lines of C#

If you want more information about fixing error that we can have in Blend (while the application works properly at run time), you can check out this post of Jaime.

StyleCop + Resharper = StyleCop for Resharper addin

If you’re a .Net developper then you MUST use ReSharper. I you don’t, I suggest you to have a look at this very nice video demonstrating some of the feature of this Visual Studio addin. If you also like having a clean C# code, then you might also use Microsoft StyleCop tool.

I just found this a very cool Resharper plugin that allows Microsoft StyleCop to be run as you type, generating real-time syntax highlighting of violations:

The StyleCop for Resharper plugin is hosted on CodePlex and is free. I think it’s a must have for any .Net developer. Its author really did a good work 🙂

kick it on DotNetKicks.com

Microsoft StyleCop vs Agility

When I write code, I try to keep it as clean as possible by following rules that I define and use in all my project. Those rules can be the ordering of elements within a class, or the way I choose name for my properties and methods…

Microsoft created a tool that analyzes C# source code in order to enforce a set of style and consistency rules : it’s StyleCop (available for free to download). StyleCop defines a lot of rules, for example:

  • Element must begin with an upper case letter
  • Field name must begin with a lower case letter
  • Prefix local calls with the “this” prefix

It is possible to enable or disable each rules separately, and this is what most users will do. Running StyleCop on one of your project can lead to thousands of warning. You can then choose which rules you want to keep enabled.

I started to use StyleCop the project I’m working on at job about one week ago. After disabling some of the rules I didn’t wanted to fix yet, I found a rules that was giving me a lot of warnings:

  • ALL elements must be documented

Hmm… This means that each single method or properties in my project must have a documentation… Well, if documentation is good lets start writing documentation everywhere. I though I will take a couple of classes per day, and write the entire documentation. I started with opening one of my class, and found this method:

public void OpenDocument(IDocument document)
// ...


StyleCop wasn’t happy because there wasn’t any documentation, so I wrote one:

/// Open a document
/// IDocument to open
public void OpenDocument(IDocument document)
// ...

Then, I don’t know why but I asked myself “what the hell this documentation is going to help the user of the class ???”. Because one month earlier I went to the AgileTour (a french event about Agile methods), I remembered the Agile Manifesto:

  • Individuals and interactions over processes and tools
  • Working software over comprehensive documentation
  • Customer collaboration over contract negotiation
  • Responding to change over following a plan

I was thinking a couple of minutes, and then I decided to remove the StyleCop rules about documenting EVERYTHING in my code. I think that would be a waste of time and that would preventing me to put good comments where it’s really needed such explaning an algorithm or why I choose this way over this other way to do the job.

I’m still using StyleCop to have a set of rules about the style of my code. But for now, that’s it ! I think it is very important to make the differenciation between documentation and comments. If documentation is needed because it will generate a document outside the application then it might be usefull. But if the documentation is written just to have it, I prefer forget about it.