在寻找了很多答案之后，我想出了这个简单的解决方法，我将在这里分享，希望它能帮助到其他人。

我设置WindowStyle=0x10000000。

这设置了窗口样式的WS_VISIBLE (0x10000000)和WS_OVERLAPPED (0x0)值。"Overlapped"是显示标题栏和窗口边框的必要值。通过从我的样式值中删除WS_MINIMIZEBOX (0x20000)、WS_MAXIMIZEBOX (0x10000)和WS_SYSMENU (0x80000)值，标题栏中的所有按钮都被删除了，包括关闭按钮。

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。

尝试在窗口中添加关闭事件。将此代码添加到事件处理程序中。

e.Cancel = true;

这样可以防止窗口关闭。这与隐藏关闭按钮具有相同的效果。

使用这个，从https://stephenhaunts.com/2014/09/25/remove-the-close-button-from-a-wpf-window修改:

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);
        }  

    }
}

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。

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>