Never ever close me – how to disable close button in WPF

Well, there is no such option in WPF. The only thing you can do is to go a bit down to unmanaged and hook WM messages to apply your own style to the system menu. How to do it?

First of all, we have to know to to hook system events in WPF. For such action, we have HwndSource. I wrote a bit about it here and here, so it’s the simple one.

 protected override void OnSourceInitialized(EventArgs e)        {            base.OnSourceInitialized(e);

            HwndSource hwndSource = PresentationSource.FromVisual(this) as HwndSource;

            if (hwndSource != null)            {                hwndSource.AddHook(new HwndSourceHook(this.hwndSourceHook));            }

        }

        IntPtr hwndSourceHook(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled)        {

Next, let’s do a bit of Interop

[DllImport("user32.dll")]        static extern IntPtr GetSystemMenu(IntPtr hWnd, bool bRevert);        [DllImport("user32.dll")]        static extern bool EnableMenuItem(IntPtr hMenu, uint uIDEnableItem, uint uEnable);

        const uint MF_BYCOMMAND = 0x00000000;        const uint MF_GRAYED = 0x00000001;        const uint MF_ENABLED = 0x00000000;

        const uint SC_CLOSE = 0xF060;

        const int WM_SHOWWINDOW = 0x00000018;        const int WM_CLOSE = 0x10;

And now, we can hook WM_SHOWWINDOW and WM_CLOSE to apply those styles

IntPtr hwndSourceHook(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled)        {            if (msg == WM_SHOWWINDOW)            {                IntPtr hMenu = GetSystemMenu(hwnd, false);                if (hMenu != IntPtr.Zero)                {                    EnableMenuItem(hMenu, SC_CLOSE, MF_BYCOMMAND | MF_GRAYED);                }            }            else if (msg == WM_CLOSE)            {                handled = true;            }            return IntPtr.Zero;        }

We done. Now just think about how to close such window Happy programming

6 Responses to “Never ever close me – how to disable close button in WPF”

Ron Says:
January 1st, 2009 at 12:23 am
Great post. Please add:

using System.Windows.Interop;

using System.Runtime.InteropServices;
Just code - Tamir Khason Says:
January 1st, 2009 at 12:23 am
Challenge: create visual clipboard watcher, that displays and saves Bitmaps right after they arrives
Tamir Khason Says:
January 1st, 2009 at 12:23 am
Gagan, thank you for response. The point in this article is not to prevent the window from closing, but disable close button in the window system menu
Gagan Rajpal Says:
January 1st, 2009 at 12:23 am
There is a much simpler but WPF solution too:

Just subscribe to the Windows Closing Event and in the handler set e.Cancel = true

eg:

public partial class Window1 : Window

{

public Window1()

{

InitializeComponent();

this.Closing += new System.ComponentModel.CancelEventHandler(Window1_Closing);

}

void Window1_Closing(object sender, System.ComponentModel.CancelEventArgs e)

{

e.Cancel = true;

}

}
Nick Says:
July 15th, 2009 at 8:09 am
Can you please change the source code color……..it’s really not readable. I mean light blue and light green they are not clearly visible
YOU UGLY MAMA Says:
September 15th, 2009 at 11:45 am
HEY YOU DUMB AHOLE TAMIT THE HOMO HOW ABOUT POSTING A WPF PROJECT WITH SOURCE INSTEAD OF JUST COPYING AND PASTING

Tamir Khason – Just code

Never ever close me – how to disable close button in WPF

6 Responses to “Never ever close me – how to disable close button in WPF”

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