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>

我只是使用交互性行为(你需要引用System.Windows.Interactivity)添加了我对Joe White的答案的实现。

代码:

public class HideCloseButtonOnWindow : Behavior<Window>
{
    #region bunch of native methods

    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

    protected override void OnAttached()
    {
        base.OnAttached();
        AssociatedObject.Loaded += OnLoaded;
    }

    protected override void OnDetaching()
    {
        AssociatedObject.Loaded -= OnLoaded;
        base.OnDetaching();
    }

    private void OnLoaded(object sender, RoutedEventArgs e)
    {
        var hwnd = new WindowInteropHelper(AssociatedObject).Handle;
        SetWindowLong(hwnd, GWL_STYLE, GetWindowLong(hwnd, GWL_STYLE) & ~WS_SYSMENU);
    }
}

用法:

<Window x:Class="WpfApplication2.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"
        xmlns:w="clr-namespace:WpfApplication2">

    <i:Interaction.Behaviors>
        <w:HideCloseButtonOnWindow />
    </i:Interaction.Behaviors>

</Window>

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">

要禁用关闭按钮，你应该添加以下代码到你的Window类(代码是从这里，编辑和重新格式化一点):

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;
}

这段代码还禁用了系统菜单中的关闭项，并禁止使用Alt+F4关闭对话框。

您可能希望以编程方式关闭该窗口。仅仅调用Close()是行不通的。你可以这样做:

allowClosing = true;
Close();

让用户“关闭”窗口，但实际上只是隐藏它。

在窗口的OnClosing事件中，隐藏已经可见的窗口:

    If Me.Visibility = Windows.Visibility.Visible Then
        Me.Visibility = Windows.Visibility.Hidden
        e.Cancel = True
    End If

每次后台线程执行时，重新显示后台UI窗口:

    w.Visibility = Windows.Visibility.Visible
    w.Show()

当终止程序执行时，确保所有窗口都是/可以关闭的:

Private Sub CloseAll()
    If w IsNot Nothing Then
        w.Visibility = Windows.Visibility.Collapsed ' Tell OnClosing to really close
        w.Close()
    End If
End Sub