I was writing a custom control today - started by using the VS 2005 "Add New Item..." dialog. After providing the filename, it barfed with a message "Value does not fall within the expected range". Obviously the new item wizard doesn't like something about my project. It actually created the code-behind file successfully, but nothing else, so I was left to setup the themes\generic.xaml file myself. Easy enough, right?

Created a simple folder in the project, called it "themes", then created a simple generic.xaml file, which contained a ResourceDictionary. Now when using the custom control from some window, I would get nothing. argh. Looked at the compile settings for generic.xaml, Build Action "Page", "Do not copy" ... looks good. Struggled around for a bit, then finally compared to another VS 2005 project started from scratch, where the add new item works.

The answer: AssemblyInfo.cs needs a ThemeInfo attribute.
Mine looks like this (sans comments), and it all seems to work now...

Another from the "not necessarily related to .NET proper" category ...

I'm doing quite a bit of manual merging of source code files lately, and am trying to come up with the best process and toolset to do so. In order of age, there's WinDiff (ancient Win32 days), then the SourceSafe diff tool, and TFS. There are a ton more, but those are what are in my current arsenal.

I know that TFS is extensible in terms of the diff and merge tools, allowing you to point it at whatever tool you want. Turns out, their default tool is a standalone tool: DIFFMERGE.EXE Since we're not using TFS for these source files I'm merging, I played with using that as a stand-alone tool. The highlights:

• You have to provide file path information on the command-line, which is a bit painful
• Can't compare directories - it's one file at a time
  
• Merge results are immediately saved in the 3rd pane to a given file (pretty cool)
  

Knowing that TFS allows this extensibility to plugin other tools, I searched for the diffmerge tool. Found this post from James Manning about the various tools that are out there.

WinMerge - merge can disregard whitespace, can't automatically edit the resulting file. Looks like you have to copy/paste into the 3rd window.

KDiff3 - UI looks very non-Windows-ish, but feature set rocks. Commands to take content from file1 or 2 and shove it in the right spot in the merge results file. Save the merge results at the end.

So as of now - the winner is KDiff3. I'll be using it for my next merge operation.

I've been experimenting with Visual Studio Orcas (beta 1) lately, to see if it's any better, particularly in 2 places where I'm having pain writing WPF apps in VS 2005:

1. Showing XAML files in design view, if they contain UserControls, or represent a custom class that derives from a WPF control type.
2. Describing the ACTUAL error when there's a problem loading a XAML file. (the dreaded "Cannot create instance of XYZ defined in assembly ABC... blah.xaml, line 2, position 5". Of course, that location in the file is nowhere near the code causing error (it's usually the first namespace declaration for the outermost element in the XAML file).
   

I'm happy to report, that with Orcas, both problems are fixed (at least to some extent)!

1. After wading through seemingly tighter, more picky error reporting by the Orcas designer, I have been able to view my UserControl and custom class derived XAML files in deisgner mode!!
2. I just ran into the error in XAML file exception in VS05, loaded up the same solution in Orcas, and the exception there pinpointed the line (and character!) where the problem was (still a little funny - the error was in the code-behind for a custom class, failing on a DependencyProperty.Register method [bad parameter type FrameworkPropertyMetadata instead of UIPropertyMetadata?] -- so the error shows up in the XAML file that contains that failing class).

Now that I'm in full swing WPF development, there's definitely a tendency by the customers to do whacky things in the UI.

Here's a list of UI guidelines / rules to adhere to.

MSDN: Top Rules for the Windows Vista User Experience