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。

XAML 代码

<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>

应该工作

编辑-在你的瞬间，这个线程展示了如何做到这一点，但我不认为窗口有一个属性来获得你想要的而不失去正常的标题栏。

编辑2 这个线程展示了一种方法，但你必须将自己的风格应用到系统菜单，它展示了一种方法，你可以这样做。

如果需要的只是禁止用户关闭窗口，这是一个简单的解决方案。

XAML守则: IsCloseButtonEnabled =“虚假”

它挡住了按钮。

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。

要设置的属性是=> WindowStyle="None"

<Window x:Class="mdaframework.MainWindow"
            xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
            xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
            Title="Start" Height="350" Width="525" ResizeMode="NoResize"  WindowStartupLocation="CenterScreen" WindowStyle="None">

我非常喜欢这个答案，它使用附加属性来调节行为。然而，我发现答案的实现过于复杂，它也没有解决防止窗口关闭的次要目标，即使使用Alt+F4。所以我提供了另一种选择:

enum CloseButtonVisibility
{
    Visible,
    Hidden,
    CloseDisabled,
}

static class WindowEx
{
    private static readonly CancelEventHandler _cancelCloseHandler = (sender, e) => e.Cancel = true;

    public static readonly DependencyProperty CloseButtonVisibilityProperty =
        DependencyProperty.RegisterAttached(
            "CloseButtonVisibility",
            typeof(CloseButtonVisibility),
            typeof(WindowEx),
            new FrameworkPropertyMetadata(CloseButtonVisibility.Visible, new PropertyChangedCallback(_OnCloseButtonChanged)));

    [AttachedPropertyBrowsableForType(typeof(Window))]
    public static CloseButtonVisibility GetCloseButtonVisibility(Window obj)
    {
        return (CloseButtonVisibility)obj.GetValue(CloseButtonVisibilityProperty);
    }

    [AttachedPropertyBrowsableForType(typeof(Window))]
    public static void SetCloseButtonVisibility(Window obj, CloseButtonVisibility value)
    {
        obj.SetValue(CloseButtonVisibilityProperty, value);
    }

    private static void _OnCloseButtonChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        if (!(d is Window window))
        {
            return;
        }

        if (e.OldValue is CloseButtonVisibility oldVisibility)
        {
            if (oldVisibility == CloseButtonVisibility.CloseDisabled)
            {
                window.Closing -= _cancelCloseHandler;
            }
        }

        if (e.NewValue is CloseButtonVisibility newVisibility)
        {
            if (newVisibility == CloseButtonVisibility.CloseDisabled)
            {
                window.Closing += _cancelCloseHandler;
            }

            if (!window.IsLoaded)
            {
                // NOTE: if the property is set multiple times before the window is loaded,
                // the window will wind up with multiple event handlers. But they will all
                // set the same value, so this is fine from a functionality point of view.
                //
                // The handler is never unsubscribed, so there is some nominal overhead there.
                // But it would be incredibly unusual for this to be set more than once
                // before the window is loaded, and even a handful of delegate instances
                // being around that are no longer needed is not really a big deal.
                window.Loaded += _ApplyCloseButtonVisibility;
            }
            else
            {
                _SetVisibility(window, newVisibility);
            }
        }
    }

    #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 void _ApplyCloseButtonVisibility(object sender, RoutedEventArgs e)
    {
        Window window = (Window)sender;
        CloseButtonVisibility visibility = GetCloseButtonVisibility(window);

        _SetVisibility(window, visibility);
    }

    private static void _SetVisibility(Window window, CloseButtonVisibility visibility)
    {
        var hwnd = new WindowInteropHelper(window).Handle;

        if (visibility == CloseButtonVisibility.Visible)
        {
            SetWindowLong(hwnd, GWL_STYLE, GetWindowLong(hwnd, GWL_STYLE) | WS_SYSMENU);
        }
        else
        {
            SetWindowLong(hwnd, GWL_STYLE, GetWindowLong(hwnd, GWL_STYLE) & ~WS_SYSMENU);
        }
    }
}

这提供了三种状态可供选择:

可见 隐藏，但用户仍然可以使用Alt+F4关闭 隐藏，关闭是完全禁用的

请注意，默认情况下，永不关闭的窗口将防止WPF程序的进程终止。如果你选择使用CloseButtonVisibility。值CloseDisabled时，您将需要定制Application.Run()行为，或者在退出前重新启用关闭窗口。例如，在你的主窗口中，你可能会有这样的东西:

protected override void OnClosed(EventArgs e)
{
    WindowEx.SetCloseButtonVisibility(this.toolWindow.Value, CloseButtonVisibility.Hidden);
    this.toolWindow.Value.Close();

    base.OnClosed(e);
}

其中toolWindow是关闭按钮被禁用的窗口的窗口引用。

上面假设在正常的UI活动期间，窗口通常只是隐藏并根据需要显示。当然，您也可以选择在任何时候显式地关闭窗口，但是同样的技术—将选项设置为不禁用关闭，然后显式地关闭窗口—仍然适用。