title: Cannot use pinvoke to send WM_CLOSE to a Windows Explorer window
body: <p>I have a C# application that uses the SendMessage pinvoke method to send a "close window" message (WM_CLOSE / 16) to various windows outside the application.  This works great, except when the window in question is a Windows Explorer window.  I do not get an exception, but the window does not close.</p>
  
  <p>Here's the signature:</p>
  
  <pre><code>    [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = false)]
      internal static extern IntPtr SendMessage(HandleRef hWnd, uint Msg, IntPtr wParam, IntPtr lParam);
  </code></pre>
  
  <p>Is there a different message that I need to send to Windows Explorer windows?  Or an alternate way to accomplish this?</p>