WPF无边框窗口的DropShadow

我已经编写了一个小的实用程序类,它能够完全满足您的需要:在无边界图像上放置一个标准阴影 Window 但是有 AllowsTransparency 设置为 false

你只要打电话给警察就行了 DropShadowToWindow(Window window) 方法。最好是在窗口的构造函数的 InitializeComponent() ,但即使在显示窗口后调用它,它也会工作。

using System;
using System.Drawing.Printing;
using System.Runtime.InteropServices;
using System.Windows;
using System.Windows.Interop;

public static class DwmDropShadow
{
    [DllImport("dwmapi.dll", PreserveSig = true)]
    private static extern int DwmSetWindowAttribute(IntPtr hwnd, int attr, ref int attrValue, int attrSize);

    [DllImport("dwmapi.dll")]
    private static extern int DwmExtendFrameIntoClientArea(IntPtr hWnd, ref Margins pMarInset);

    /// <summary>
    /// Drops a standard shadow to a WPF Window, even if the window is borderless. Only works with DWM (Windows Vista or newer).
    /// This method is much more efficient than setting AllowsTransparency to true and using the DropShadow effect,
    /// as AllowsTransparency involves a huge performance issue (hardware acceleration is turned off for all the window).
    /// </summary>
    /// <param name="window">Window to which the shadow will be applied</param>
    public static void DropShadowToWindow(Window window)
    {
        if (!DropShadow(window))
        {
            window.SourceInitialized += new EventHandler(window_SourceInitialized);
        }
    }

    private static void window_SourceInitialized(object sender, EventArgs e)
    {
        Window window = (Window)sender;

        DropShadow(window);

        window.SourceInitialized -= new EventHandler(window_SourceInitialized);
    }

    /// <summary>
    /// The actual method that makes API calls to drop the shadow to the window
    /// </summary>
    /// <param name="window">Window to which the shadow will be applied</param>
    /// <returns>True if the method succeeded, false if not</returns>
    private static bool DropShadow(Window window)
    {
        try
        {
            WindowInteropHelper helper = new WindowInteropHelper(window);
            int val = 2;
            int ret1 = DwmSetWindowAttribute(helper.Handle, 2, ref val, 4);

            if (ret1 == 0)
            {
                Margins m = new Margins { Bottom = 0, Left = 0, Right = 0, Top = 0 };
                int ret2 = DwmExtendFrameIntoClientArea(helper.Handle, ref m);
                return ret2 == 0;
            }
            else
            {
                return false;
            }
        }
        catch (Exception ex)
        {
            // Probably dwmapi.dll not found (incompatible OS)
            return false;
        }
    }
}

Patrick的答案很好用,除了win32窗口是托管的。 当这种情况发生时,您会注意到托管窗口被“冲掉”(看起来windows正在将“玻璃板”效果应用于整个托管窗口)。 例如

[StructLayout(LayoutKind.Sequential)]
public struct Margins
{
    public int Left;
    public int Right;
    public int Top;
    public int Bottom;
}  

如果允许窗口调整边框大小,请通过设置 ResizeMode 到 CanResize MaxWidth , MinWidth , MaxHeight MinHeight 设置为阻止调整大小的值。

如果您有一个没有样式的无边框窗口,那么您必须在自己的视觉树中提供该窗口的所有外观,包括一个阴影,因为这种设置组合与表示您不想要操作系统提供的内容是一样的。

从那时起,如果窗口大小是固定的,只需添加dropshadow,也许作为一个 <Rectangle/> <Canvas/>

像这样:

<Window x:Class="MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="MainWindow" AllowsTransparency="True" Background="Transparent" WindowStyle="None">
    <Canvas>
        <Rectangle Fill="#33000000" Width="100"  Height="100"/>
        <Rectangle Fill="#FFFF0000" Width="95"  Height="95" />
    </Canvas>
</Window>

Fill 第一个的属性 Rectangle 是部分透明的,您也可以使用 Opacity 矩形 . 您可以使用自己的图形或其他形状,自定义放置阴影的外观。

AllowsTransparency 是 False ,但你别无选择:如果你想要透明,你必须允许它。

为什么不创建一个与你的“窗口”相同的物体的阴影,但是在它后面更大。

<Window x:Class="WPF_Custom_Look.ShadowWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="ShadowWindow" Height="400" Width="450" ResizeMode="NoResize" Background="Transparent" AllowsTransparency="True" WindowStyle="None">
<Grid>
    <Rectangle Fill="Black" Width="330" Opacity="0.5" Height="279">
        <Rectangle.Effect>
            <BlurEffect Radius="30"/>
        </Rectangle.Effect>
    </Rectangle>
    <Rectangle Fill="#FFFDFDFD" Width="312"  Height="260"/>

</Grid>

或者如果你需要一个透明的标题栏,可以用 <Border>

<Canvas>
    <Border BorderBrush="Black" BorderThickness="7" Height="195" Width="304" Canvas.Left="53" Canvas.Top="25">
        <Border.Effect>
            <BlurEffect Radius="20"/>
        </Border.Effect>
    </Border>
    <Rectangle Fill="#FF86B0F9" Width="285"  Height="177" Opacity="0.7" Canvas.Left="62" Canvas.Top="34" MouseDown="Border_MouseDown"/>
    <Rectangle Fill="#FFFDFDFD" Width="285"  Height="143" Canvas.Left="62" Canvas.Top="68"/>
</Canvas>