How to use dll from Mono in Windows Forms project?

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Mono

C#

.NET

WinForms

Gtk#

I would like to use simple dll compiled in Mono(GTK), in WinForms in Visual Studio.
I added references in VS to gtk-sharp, Mono.Cairo/Posix, gtk-dotnet, atk-sharp

I'm starting to work with mono and before I proceed to work on more important things in mono I have to make sure that the dlls written in mono, will work with other projects in Visual Studio. Could someone give an example of code that will open a the windows/dilalog in WinForms?
When I'm running my code, i get an error:

System.AccessViolationException was unhandled
  HResult=-2147467261
  Message=Attempted to read or write protected memory. Often, this indicates that the other memory is corrupt.
  Source=gtk-sharp
  StackTrace:
       w Gtk.Dialog.gtk_dialog_run(IntPtr raw)
       w Gtk.Dialog.Run()
       w dllTest.MessageBox.Show(String Msg)
       w dllTest.MyClass.Test()
       w AllegroParser.Form1.Form1_Load(Object sender, EventArgs e) w C:\Users\KrzysiekJ\Documents\Visual Studio 2010\Projects\AllegroParser\AllegroParser\Form1.cs:wiersz 23
       w System.Windows.Forms.Form.OnLoad(EventArgs e)
       w System.Windows.Forms.Form.OnCreateControl()
       w System.Windows.Forms.Control.CreateControl(Boolean fIgnoreVisible)
       w System.Windows.Forms.Control.CreateControl()
       w System.Windows.Forms.Control.WmShowWindow(Message& m)
       w System.Windows.Forms.Control.WndProc(Message& m)
       w System.Windows.Forms.ScrollableControl.WndProc(Message& m)
       w System.Windows.Forms.ContainerControl.WndProc(Message& m)
       w System.Windows.Forms.Form.WmShowWindow(Message& m)
       w System.Windows.Forms.Form.WndProc(Message& m)
       w System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
       w System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
       w System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)

Dll code:

namespace dllTest
{
   public class MyClass
   {
      public MyClass ()
      {
      }
      public void Test ()
      {
         MessageBox.Show ("test");
      }
   }
   public class MessageBox
   {
      public static void Show(string Msg)
      {
         MessageDialog md = new MessageDialog (null, DialogFlags.Modal, MessageType.Info, ButtonsType.Ok, Msg);
         md.Run ();
         md.Destroy();
      }
   }
}

Simple app in WinForms:

dllTest.MyClass mc = new dllTest.MyClass();
mc.Test();