Core Function GUIMsgFilter

// Create the MDI GUI
$GUI = GUICreate("MDIWindow", "GUI", 800, 600);
// Show the MDI GUI
GUILoad( $GUI );
 
// Create the Design Window
$Window = GUICreate("Window", "GUI", 640, 482, 0, 0);
GUIMDIParent($Window, $GUI);
// Show the Design Window
GUILoad( $Window );
 
// Create the GUI objects
$b1 = GUICreate("Button", $Window, "Send", 8, 8);
 
// Add a link
GUILink($b1, "Click", 'Send();');
 
// Create the GUI msgFilter
GUIMsgFilter($Window, "myMsgFilter();");
 
// Keep the GUI running as long as long as the window is open
While ( GUIStatus( $GUI ) ) DoEvents( );
 
// When you create a msgfilter 4 variables are automatically created for you
// $HWND
// $MSG
// $WPARAM
// $LPARAM
// All them names should be familiar to you
Function myMsgFilter()
{
	println("HWND: " . $HWND . " | MSG: " . $MSG . " | WParam: " . $WParam . " | LParam: " . $LParam);
	return 0; // If you return HIGHER than 0 the msgfilter will be removed
}
 
// The button click goes here this will simply just be something to test out the msgFilter
Function Send()
{
	$Handle = GUIGetProp($GUI, "Handle"); // Get the HWND of our window
	// Send a message to the window containing 2 unique numbers 777 and 1337
	// Just to see if they appear in the filter
	DLLCall("user32.dll", "PostMessage", "Int32", "iIII", $Handle, 160, 777, 1337);
}