The type or namespace name 'Window' does not exist in the namespace 'System.Windows'

Question

I am trying to write an extension method for the WPF Window class. I am doing it in a class library project in my solution, so that I can use it in all my projects in the solution.

Here is my code:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;

namespace ExtensionMethods
{
    public static class MyExtensions
    {
        public static void ResizeToPrimaryScreenWorkingArea(this System.Windows.Window w)
        { 
        }
    }
}

When I try to compile this, I get the following error:

The type or namespace name 'Window' does not exist in the namespace 'System.Windows'

Yes, I DID add references to System.Windows and System.Windows.Forms in my class library project, and they are showing under References in the project in Solution Explorer.

What am I doing wrong?

Answer 1

Add PresentationFramework.dll reference to your project it contains the System.Windows namespace.

http://msdn.microsoft.com/es-es/library/system.windows.window(v=vs.110).aspx