I want to create a control as a child of another window which is in
another process. (I am trying to implement preview for a screen saver
written in C#). In order to do that I have code like this:-
public class PreviewWindow : System.Windows.Forms.Control
{
private IntPtr parentHandle;
public PreviewWindow(IntPtr parent)
{
this.parentHandle = parent;
}
const int WS_VISIBLE = 0x10000000;
const int WS_CHILD = 0x40000000;
protected override System.Windows.Forms.CreateParams
CreateParams
{
get
{
System.Windows.Forms.CreateParams cp =
base.CreateParams;
cp.Style = WS_VISIBLE | WS_CHILD;
cp.Parent = parentHandle;
UnmanagedMethods.RECT rect = new
UnmanagedMethods.RECT();
UnmanagedMethods.GetClientRect(parentHandle, ref rect);
cp.X = rect.left;
cp.Y = rect.top;
cp.Height = rect.Height;
cp.Width = rect.Width;
return cp;
}
}
}
This code successfully creates the control as a child window but when
WM_CLOSE message is sent to the Child Window (this control), the parent
window gets closed. In case of screen saver the desktop settings dialog
box disappears. It looks like (ILDASM) in response to WM_CLOSE the
implementation Control sends WM_CLOSE to the top most parent. Any idea
why this has been implemented like that? This is surely a bug. The only
workaround is to handle WM_CLOSE in the WndProc function.
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