How to get Handle of a form that hosts a COM-Control

Question

I have a visual DotNet-Control that I use as COM-Control in a Delphi project.
Now I want to get the handle of the delphi form that hosts this DotNet-component in DotNet. Sure - i could pass the Form's handle from Delphi to DotNet using something like a setParentHandle(pHandle: hwnd); method that I define, but this is not the way I want to do it here.

Is there any Winapi call that can give me the handle of a component that I draw something on in DotNet?

I want to use this handle in order to send Messages that can not be handled by the DotNetComponent itself to the Delphi Form.

Answer 1

I resolved this using the GetParent method of WinApi just like this in C#.

[DllImport("user32.dll")]
private static extern IntPtr GetParent(IntPtr hWnd);

protected override void WndProc(ref Message m){

    // 0x20a is the Message constant for WM_MOUSEWHEEL (Scrolling on your control)
    if(m.Msg == 0x20a){
      IntPtr hWnd= GetParent(this.Handle);
      SendMessage(hWnd, m.Msg, m.WParam, m.LParam);
    }
    else
        base.WndProc(ref m);
}

Remark: Forwarding all messages to the parent control will break your Control since it won't receive its own messages any longer.