How to hide close button in WPF window?

Question

I'm writing a modal dialog in WPF. How do I set a WPF window to not have a close button? I'd still like for its WindowState to have a normal title bar.

I found ResizeMode, WindowState, and WindowStyle, but none of those properties allow me to hide the close button but show the title bar, as in modal dialogs.

Answer 1

To disable close button you should add the following code to your Window class (the code was taken from here, edited and reformatted a bit):

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

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

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

}

private bool allowClosing = false;

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

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

private const uint SC_CLOSE = 0xF060;

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

private IntPtr HwndSourceHook(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled)
{
    switch (msg)
    {
        case WM_SHOWWINDOW:
            {
                IntPtr hMenu = GetSystemMenu(hwnd, false);
                if (hMenu != IntPtr.Zero)
                {
                    EnableMenuItem(hMenu, SC_CLOSE, MF_BYCOMMAND | MF_GRAYED);
                }
            }
            break;
        case WM_CLOSE:
            if (!allowClosing)
            {
                handled = true;
            }
            break;
    }
    return IntPtr.Zero;
}

This code also disables close item in System menu and disallows closing the dialog using Alt+F4.

You will probably want to close the window programmatically. Just calling Close() will not work. Do something like this:

allowClosing = true;
Close();

Answer 2

XAML Code

<Button Command="Open" Content="_Open">
    <Button.Style>
        <Style TargetType="Button">
            <Style.Triggers>
                <Trigger Property="IsEnabled" Value="False">
                    <Setter Property="Visibility" Value="Collapsed" />
                </Trigger>
            </Style.Triggers>
        </Style>
     </Button.Style>
</Button>

should work

Edit- for your instant this Thread shows how that can be done but I don't think Window has a property to get what you want without losing the normal title bar.

Edit 2 This Thread shows a way for it to be done, but you must apply your own style to the system menu and it shows a way how you can do that.

Answer 3

Try adding a Closing event to the window. Add this code to the event handler.

e.Cancel = true;

This will prevent the window from closing. This has the same effect as hiding the close button.

Answer 4

Use this, modified from https://stephenhaunts.com/2014/09/25/remove-the-close-button-from-a-wpf-window :

using System;
using System.Runtime.InteropServices;
using System.Windows;
using System.Windows.Input;
using System.Windows.Interop;
using System.Windows.Media;

namespace Whatever
{
    public partial class MainMenu : Window
    {
        private const int GWL_STYLE = -16;
        private const int WS_SYSMENU = 0x00080000;

        [DllImport("user32.dll", SetLastError = true)]
        private static extern int GetWindowLongPtr(IntPtr hWnd, int nIndex);

        [DllImport("user32.dll")]
        private static extern int SetWindowLong(IntPtr hWnd, int nIndex, int dwNewLong);

        public MainMenu()
        {
             InitializeComponent();
             this.Loaded += new RoutedEventHandler(Window_Loaded);
        }

        private void Window_Loaded(object sender, RoutedEventArgs e)
        {
            var hwnd = new WindowInteropHelper(this).Handle;
            SetWindowLongPtr(hwnd, GWL_STYLE, GetWindowLongPtr(hwnd, GWL_STYLE) & ~WS_SYSMENU);
        }  

    }
}

Answer 5

If the need is only to prohibit the user from closing the window, this is a simple solution.

XAML code: IsCloseButtonEnabled="False"

Answer 6

I was trying Viachaslau's answer since I like the idea of not removing the button but disabling it, but for some reason it did not always work: the close button was still enabled but no errors whatsoever.

This on the other hand always worked (error checking omitted):

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

private const uint MF_BYCOMMAND = 0x00000000;
private const uint MF_GRAYED = 0x00000001;
private const uint SC_CLOSE = 0xF060;
private const int WM_SHOWWINDOW = 0x00000018;

protected override void OnSourceInitialized( EventArgs e )
{
  base.OnSourceInitialized( e );
  var hWnd = new WindowInteropHelper( this );
  var sysMenu = GetSystemMenu( hWnd.Handle, false );
  EnableMenuItem( sysMenu, SC_CLOSE, MF_BYCOMMAND | MF_GRAYED );
}