index > Windows Forms General > Make Form modal to external hWnd

Make Form modal to external hWnd

In a screensaver, when the Options button is clicked in control panel, it calls the screen saver with the command line argument /c:1234567 (for example) where 1234567 is the window handle of the control panel dialog that my Options form needs to be made modal to.

How can I do this? I tried Control.FromHandle but it returned null.

Aero.NET Tuesday, November 22, 2005 7:50 PM

You have to create a class that implements IWin32Window:

using System;
using System.Windows.Forms;

public class Window : IWin32Window
{
private IWin32Window _Handle;

public Window(IntPtr handle)
{
  _Handle = handle;
}

public IntPtr Handle
{
  get { return _Handle; }
}
}

You can then do this:

using (Form form = new Form())
{
      form.ShowDialog(new Window((IntPtr)1234567));
}

Where 1234567 is the handle that is passed to you.

David M. Kean Tuesday, November 22, 2005 8:07 PM

Hey, there,

Any idea why this code, when translated to VB.NET, causes a compiler error? IntPtr cannot be converted to IWin32Window and vice versa.

Thanks!

Graham Charles Friday, December 09, 2005 9:02 PM

I have the same problem, and I tried your solution. but the form does not become modal, the parentform can still be selected and closed.

Any other suggestions ?

(Sorry if I am thread-necromancing with this, it's just that I did a search and this thread came up)

Thanks in advance,

Ben Blok.

boran_blok_edan Thursday, January 18, 2007 4:32 PM