How to tell which window becomes the foregroud window right away?

microsoft.public.dotnet.framework

30 Apr 2007 7:10 PM

Andrew

Hello,

I followed the MS instructions to subclass Windows using C#.net
(http://support.microsoft.com/kb/815775) as the follows. I then opened
several Excel files, and selected anyone of them as foreground window. I was
expecting to see windows message, saying WM_ACTIVATE, or something like that,
however, to my surprise, I saw NO windows message when I randomly selected
those Excel windows, (although I could see other window messages, e.g.,
WM_GETTEXT).

It was said that this was because "Subclassing this way only works for
windows in its own process, not in other applications." Then, is there a way
to make it work on other processes? Will automation will make the "other
application" in the same process of our application?

My goad is: Tell which (e.g. Excel) window becomes the active one AS SOON AS
a (e.g. Excel) window becomes active.

Thanks a lot.

--------------------
Add a new Class module that is named SubclassHWND.cs to the Visual C# .NET
or Visual C# 2005 application. To do this, click Add Class on the Project
menu.
2. In the Name text box, type SubclassHWND.cs, and then click Open.
3. Replace the SubclassHWND class code with the following code:public class
SubclassHWND : NativeWindow
{
   protected override void WndProc(ref Message m)
    {
      // Perform whatever custom processing you must have for this message
      System.Diagnostics.Debug.WriteLine(m.ToString());
     // forward message to base WndProc
     base.WndProc(ref m);
    }
}

4. To demonstrate its use, add the following code to the Load event of
Form1:SubclassHWND s = new SubclassHWND();
s.AssignHandle(this.Handle);
//Now s should be listening to the messages of the form.