WPF没有一个内置的属性来隐藏标题栏的关闭按钮，但是你可以用几行P/Invoke来做到这一点。

首先，将这些声明添加到Window类中:

private const int GWL_STYLE = -16;
private const int WS_SYSMENU = 0x80000;
[DllImport("user32.dll", SetLastError = true)]
private static extern int GetWindowLong(IntPtr hWnd, int nIndex);
[DllImport("user32.dll")]
private static extern int SetWindowLong(IntPtr hWnd, int nIndex, int dwNewLong);

然后把下面的代码放到Window的Loaded事件中:

var hwnd = new WindowInteropHelper(this).Handle;
SetWindowLong(hwnd, GWL_STYLE, GetWindowLong(hwnd, GWL_STYLE) & ~WS_SYSMENU);

这样就没有关闭按钮了。你也不会在标题栏的左边有一个窗口图标，这意味着没有系统菜单，即使你右键单击标题栏——它们都在一起。

重要提示:所有这些都是隐藏按钮。用户仍然可以关闭窗口!如果用户按下Alt+F4，或者通过任务栏关闭应用程序，窗口仍然会关闭。

如果你不想让窗口在后台线程完成之前关闭，那么你也可以覆盖OnClosing并将Cancel设置为true，就像Gabe建议的那样。

我刚遇到类似的问题，乔怀特的解决方案似乎对我来说简单而干净。我重用了它，并将其定义为Window的附加属性

public class WindowBehavior
{
    private static readonly Type OwnerType = typeof (WindowBehavior);

    #region HideCloseButton (attached property)

    public static readonly DependencyProperty HideCloseButtonProperty =
        DependencyProperty.RegisterAttached(
            "HideCloseButton",
            typeof (bool),
            OwnerType,
            new FrameworkPropertyMetadata(false, new PropertyChangedCallback(HideCloseButtonChangedCallback)));

    [AttachedPropertyBrowsableForType(typeof(Window))]
    public static bool GetHideCloseButton(Window obj) {
        return (bool)obj.GetValue(HideCloseButtonProperty);
    }

    [AttachedPropertyBrowsableForType(typeof(Window))]
    public static void SetHideCloseButton(Window obj, bool value) {
        obj.SetValue(HideCloseButtonProperty, value);
    }

    private static void HideCloseButtonChangedCallback(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        var window = d as Window;
        if (window == null) return;

        var hideCloseButton = (bool)e.NewValue;
        if (hideCloseButton && !GetIsHiddenCloseButton(window)) {
            if (!window.IsLoaded) {
                window.Loaded += HideWhenLoadedDelegate;
            }
            else {
                HideCloseButton(window);
            }
            SetIsHiddenCloseButton(window, true);
        }
        else if (!hideCloseButton && GetIsHiddenCloseButton(window)) {
            if (!window.IsLoaded) {
                window.Loaded -= ShowWhenLoadedDelegate;
            }
            else {
                ShowCloseButton(window);
            }
            SetIsHiddenCloseButton(window, false);
        }
    }

    #region Win32 imports

    private const int GWL_STYLE = -16;
    private const int WS_SYSMENU = 0x80000;
    [DllImport("user32.dll", SetLastError = true)]
    private static extern int GetWindowLong(IntPtr hWnd, int nIndex);
    [DllImport("user32.dll")]
    private static extern int SetWindowLong(IntPtr hWnd, int nIndex, int dwNewLong);

    #endregion

    private static readonly RoutedEventHandler HideWhenLoadedDelegate = (sender, args) => {
        if (sender is Window == false) return;
        var w = (Window)sender;
        HideCloseButton(w);
        w.Loaded -= HideWhenLoadedDelegate;
    };

    private static readonly RoutedEventHandler ShowWhenLoadedDelegate = (sender, args) => {
        if (sender is Window == false) return;
        var w = (Window)sender;
        ShowCloseButton(w);
        w.Loaded -= ShowWhenLoadedDelegate;
    };

    private static void HideCloseButton(Window w) {
        var hwnd = new WindowInteropHelper(w).Handle;
        SetWindowLong(hwnd, GWL_STYLE, GetWindowLong(hwnd, GWL_STYLE) & ~WS_SYSMENU);
    }

    private static void ShowCloseButton(Window w) {
        var hwnd = new WindowInteropHelper(w).Handle;
        SetWindowLong(hwnd, GWL_STYLE, GetWindowLong(hwnd, GWL_STYLE) | WS_SYSMENU);
    }

    #endregion

    #region IsHiddenCloseButton (readonly attached property)

    private static readonly DependencyPropertyKey IsHiddenCloseButtonKey =
        DependencyProperty.RegisterAttachedReadOnly(
            "IsHiddenCloseButton",
            typeof (bool),
            OwnerType,
            new FrameworkPropertyMetadata(false));

    public static readonly DependencyProperty IsHiddenCloseButtonProperty =
        IsHiddenCloseButtonKey.DependencyProperty;

    [AttachedPropertyBrowsableForType(typeof(Window))]
    public static bool GetIsHiddenCloseButton(Window obj) {
        return (bool)obj.GetValue(IsHiddenCloseButtonProperty);
    }

    private static void SetIsHiddenCloseButton(Window obj, bool value) {
        obj.SetValue(IsHiddenCloseButtonKey, value);
    }

    #endregion

}

然后在XAML中，你只需要这样设置:

<Window 
    x:Class="WafClient.Presentation.Views.SampleWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:u="clr-namespace:WafClient.Presentation.Behaviors"
    ResizeMode="NoResize"
    u:WindowBehavior.HideCloseButton="True">
    ...
</Window>

这不会消除关闭按钮，但它将阻止某人关闭窗口。

把这个放在文件后面的代码中:

protected override void OnClosing(CancelEventArgs e)
{
   base.OnClosing(e);
   e.Cancel = true;
}

You may run into the need to toggle the window state depending on what page or user control is currently being displayed. (Yes, this is an unusual scenario, but it can happen. In our case we have a user control in our application that is displayed on an external touch screen for customers to interact with. We don't want our customers to have touch access to close the screen. But the rest of the application uses standard windows frames.) To do this from the code behind of the page or user control. Note: You must run it from the Loaded event not the constructor because the control hasn't been populated in the constructor and it will throw an exception.

// To toggle it off
Window.GetWindow(this).WindowStyle = WindowStyle.None;

// To turn it back on toggle it off
Window.GetWindow(this).WindowStyle = WindowStyle.SingleBorderWindow;

这就是你的问题所在。窗口框右上方的关闭按钮不是WPF窗口的一部分，但它属于由操作系统控制的窗口框的一部分。这意味着你必须使用Win32互操作来实现。

或者，您可以使用noframe并提供您自己的“框架”或根本没有框架。

这不会隐藏按钮，但会阻止用户通过关闭窗口向前移动。

protected override void OnClosing(System.ComponentModel.CancelEventArgs e)
{            
    if (e.Cancel == false)
    {
        Application.Current.Shutdown();
    }
}