Why does VS.NET attempt to include Microsoft.Windows.Design.Extensibility for WPF and ClickOnce?

Question

I built a WPF application in VS.NET 2008 using ClickOnce deployment. It ran great on any machine that had VS.NET installed, but my business users received an error: "Unable to install or run the application. The application requires that assembly Microsoft.Windows.Design.Extensibility Version 3.5.0.0 be installed in the Global Assembly Cache (GAC) first."

I was surprised to discover that this dll is not part of the standard .NET 3.5 SP1 client installation, but somehow, my application thought it was needed. I checked my Publish tab for the project and it showed up as a prerequisite.

Oddly enough, I was able to just remove this (and all of the other Microsoft.Windows.Design.* dlls) and it just worked everywhere. I removed them from my project entirely, and everything was fine.

Can someone explain why the VS.NET 2008 project wizard forced these to be included in the project, and more importantly, why ClickOnce thought they needed to be on the client machine to run?

This is just a curiosity question, but I'm sure I'm not the first to be bitten by it. Hopefully, this post will at least save someone else the headache.

Answer 1

I found that I was using the SelectionCommands.Clear property which is inside the Microsoft.Windows.Design.Interaction namespace inside the Microsoft.Windows.Design.Extensibility Version dll.

Beats be why this dll isn't included in the .NET 3.5 install.

Answer 2

A way to find out the code that is loading the assembly is explained here:

http://social.msdn.microsoft.com/Forums/en-US/wpf/thread/755272f6-0e79-4a6d-ae50-4412d0f2bc4c

Answer 3

This is old and the OP is gone, but I ran into this today, so I thought I'd mention that my solution was removing a reference to one of the WPFToolkit references that ends with .Design.

I had referenced System.Windows.Controls.Input.Toolkit, but also had a reference to System.Windows.Controls.Input.Toolkit.Design, which should not have been there. Removed it, and all was right with the world again.