No creation of a WPF window in a DLL project?

Is there a reason why Visual Studio won't let me create a WPF window in a DLL project?

I "solved" it by creating a window in an Application Project and copying it to my DLL project. I also found that I could just create a UserControl and change the base class to "Window".

But if I had to do it this way, it's maybe because I shouldn't do it...

Solution 1:

Make sure the project type is WPF User Control Library when you create your project.

If it isn't then no sweat, just edit the csproj file and make sure the <ProjectTypeGuids> element under Project/PropertyGroup contain the following GUIDs

<ProjectTypeGuids>{60dc8134-eba5-43b8-bcc9-bb4bc16c2548};{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}</ProjectTypeGuids>

Also, make sure you reference PresentationFramework and System.Xaml in your project, or you will not get any WPF in your code.

Solution 2:

You can try adding new WPF User Control Item and change that to Window.

Add New Item->WPF->User Control

In XAML:

Change <UserControl> tag as <Window>

In CS:

Change base class from System.Windows.Controls.UserControl to System.Windows.Window.

Solution 3:

I do it this way: 1) create "WPF Application" 2) remove App.xaml 3) change Project properties -> Application Output type: to Class Library (originally there is Windows Application)

Otherwise you will get errors:

"Library project file cannot specify ApplicationDefinition element"

"The project file contains a property value that is not valid"

Solution 4:

What do you mean that Visual Studio won't let you create a WPF window in a DLL project? Do you mean that if you right click the project, there is no option to add a Window there?

If that is the case, I think that means that you created a project type that isn't a WPF project type. I encountered something similar a while back when I wanted to upgrade a WinForms project to use WPF instead - see this question for more information.