WPF and WndProc question.

Question

I want my WPF based app to listen to events from the OS (i.e. 0x0002 for window destroy, etc).

In Windows Forms programming - I simply override WndProc.

In WPF - I've implemented the following


private void loadedForm(object sender, RoutedEventArgs e)
{ 

HwndSource source = HwndSource.FromHwnd(new WindowInteropHelper(this).Handle);
source.AddHook(new HwndSourceHook(WndProc));

}



private static IntPtr WndProc(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled)
{

if (msg == WM_DESTROY)

          {
                MessageBox.Show("I saw a WM_DESTROY!");
                handled = true;
          } 

return IntPtr.Zero;

}

For obious reasons - I only get the message box when I close MY application. How would I implement an application (WPF based) to listent to system events (i.e. detect closing of windows for ALL windows and not just my app). I also want to detect other messages so utilizing WndProc is pretty much my only option. Help greatly appreciated.

Answer 1

 

At present, I known maybe you can use win32 hook like this:

support.microsoft.com/kb/Q318804

 

But maybe there is more better mthod thait I don't known.

Answer 2

I have tried using your code.
only that I used WM_QUERYENDSESION.
I was trying to imitate the behavior where user shutsdown/restart/logoff,
my application propts for "Do you want to save changes?" then close the file i'm using.
However nothing happens when I click yes/no, my application does not close. and if I try to close it again using the close button, I receive an error? why is this so? is it because of the Hook??

Answer 3

About WM_QUERYENDSESION, I want to cancel the closing of Windows

Can u help me?