Showing Dialogs in STA (very useful when dealing with SAP forms)

gistfile1.cs

public static class FileDialogExtension
{
  internal class SapMainWindow : IWin32Window
  {
      [DllImport("user32.dll")]
      private static extern IntPtr GetForegroundWindow();

      public IntPtr Handle { get { return GetForegroundWindow(); } }
  }

  internal class DialogState
  {
      public DialogResult Result;
      public FileDialog Dialog;

      public void ThreadProcShowDialog()
      {
          Result = Dialog.ShowDialog(new SapMainWindow());
      }
  }

  // ReSharper disable once InconsistentNaming
  public static DialogResult ShowDialogSTA(this FileDialog dialog)
  {
      var state = new DialogState { Dialog = dialog };
      var t = new System.Threading.Thread(state.ThreadProcShowDialog);
      t.SetApartmentState(System.Threading.ApartmentState.STA);
      t.Start();
      t.Join();
      return state.Result;
  }
}