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>

下面是我如何实现类似的目标使用自定义样式没有DllImports和P/Invoke调用。这删除现有的标题栏使用WindowStyle="none"，并显示一个'TextBlock'与类似的背景颜色表明作为标题栏。

XAML 代码

<Window x:Class="AddBook"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:controls="http://wpftoolkit.my-libraries.com/v5" 
    WindowStartupLocation="CenterOwner"        
    ResizeMode="NoResize" 
    Style="{DynamicResource WindowStyleX}"
    ShowInTaskbar="False"
    ShowActivated="True"
    SizeToContent="Height"
    Title="Add New Book" 
    Width="450">
..............

</Window>

XAML

<Style x:Key="WindowStyleX" TargetType="{x:Type Window}">
<Setter Property="WindowStyle" Value="None" />
<Setter Property="AllowsTransparency" Value="False" />
<Setter Property="ResizeMode" Value="NoResize" />
<Setter Property="Background" Value="White" />
<Setter Property="BorderThickness" Value="1" />
<Setter Property="Template">
    <Setter.Value>
        <ControlTemplate TargetType="{x:Type Window}">
            <Border BorderBrush="{DynamicResource BlackColor}" BorderThickness="1">
                <Grid Background="{TemplateBinding Background}">
                    <Grid.RowDefinitions>
                        <RowDefinition Height="30" />
                        <RowDefinition Height="*" />
                    </Grid.RowDefinitions>
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition />
                        <ColumnDefinition Width="Auto" />
                    </Grid.ColumnDefinitions>
                    <Border
                        Grid.Row="0"
                        Grid.ColumnSpan="2"
                        Background="{DynamicResource BlackColor}">
                        <Grid>
                            <TextBlock
                                Grid.Column="1"
                                Margin="10,0,0,0"
                                HorizontalAlignment="Left"
                                VerticalAlignment="Center"
                                FontSize="16"
                                Foreground="{DynamicResource WhiteTextForeground}"
                                Text="{TemplateBinding Title}" />
                        </Grid>
                    </Border>
                    <ContentPresenter Grid.Row="1" />
                </Grid>
            </Border>
        </ControlTemplate>
    </Setter.Value>
</Setter>

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;
}

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。

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;