详解C# wpf如何嵌入hwnd窗口

2024-03-27 08:38:11 作者：CodeOfCC

wpf是Direct UI,窗口中只有一个hwnd句柄,大部分控件都是直接在上面绘制的,本文主要来和大家讲讲如何嵌入hwnd窗口,感兴趣的可以了解一下

前言

wpf是Direct UI，窗口中只有一个hwnd句柄，大部分控件都是直接在上面绘制的。当我们需要使用不同的渲染方式进行绘制时，就会和控件绘制产生冲突。比如使用opengl渲染3d图形或者视频时，直接在窗口绘制就会出现闪烁，与控件相互覆盖。要解决这个问题就需要，添加一个新的hwnd窗口或控件嵌入wpf窗口中，我们可以通过HwndHost就可以实现这样的功能。

一、如何实现

1、继承HwndHost

public class MyWindowHost : HwndHost

2、实现抽象方法

只需实现下列2个方法

protected override HandleRef BuildWindowCore(HandleRef hwndParent)
{
    Handle =创建的窗口句柄
    return new HandleRef(this, Handle);
}

protected override void DestroyWindowCore(HandleRef hwnd)
{
   hwnd.Handle;//根据句柄销毁窗口
}

3、xaml中使用HwndHost控件

<local:MyWindowHost Width="100" Height="100" >
</local:MyWindowHost >

二、具体实现

1、Win32窗口

我们可以通过win32 api创建一个窗口，封装成HwndHost对象，提供给xaml使用。

Win32WindowHost.cs

using System.Runtime.InteropServices;
using System.Windows;
using System.Windows.Interop;
namespace WpfHwndElement
{
    /// <summary>
    /// 直接通过win32 api创建窗口
    /// </summary>
    public class Win32WindowHost : HwndHost
    {
        //重新定义Handle为依赖属性，可以用于绑定
        new public IntPtr Handle
        {
            get { return (IntPtr)GetValue(HandleProperty); }
            private set { SetValue(HandleProperty, value); }
        }
        // Using a DependencyProperty as the backing store for Hwnd.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty HandleProperty =
            DependencyProperty.Register("Handle", typeof(IntPtr), typeof(Win32WindowHost), new PropertyMetadata(IntPtr.Zero));
        protected override HandleRef BuildWindowCore(HandleRef hwndParent)
        {
            Handle = CreateWindowEx(0, "static", "", WS_CHILD | WS_VISIBLE | LBS_NOTIFY | WS_CLIPSIBLINGS, 0, 0, (int)Width, (int)Height, hwndParent.Handle, IntPtr.Zero, IntPtr.Zero, 0);
            return new HandleRef(this, Handle);
        }
        [DllImport("user32.dll", SetLastError = true)]
        static extern System.IntPtr DefWindowProcW(IntPtr hWnd, uint msg, IntPtr wParam, IntPtr lParam);

        protected override void DestroyWindowCore(HandleRef hwnd)
        {
            DestroyWindow(hwnd.Handle);
        }
        const int WS_CHILD = 0x40000000;
        const int WS_VISIBLE = 0x10000000;
        const int LBS_NOTIFY = 0x001;
        const int WS_CLIPSIBLINGS = 0x04000000;
        [DllImport("user32.dll")]
        internal static extern IntPtr CreateWindowEx(int exStyle, string className, string windowName, int style, int x, int y, int width, int height, IntPtr hwndParent, IntPtr hMenu, IntPtr hInstance, [MarshalAs(UnmanagedType.AsAny)] object pvParam);
        [DllImport("user32.dll")]
        static extern bool DestroyWindow(IntPtr hwnd);
    }
}

2、HwndSource窗口

如果不想导入win32 api，则可以使用HwndSource对象创建句柄窗口。

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

namespace WpfHwndElement
{
    class HwndSourceHost : HwndHost
    {
        //重新定义Handle为依赖属性，可以用于绑定
        new public IntPtr Handle
        {
            get { return (IntPtr)GetValue(HandleProperty); }
            private set { SetValue(HandleProperty, value); }
        }
        // Using a DependencyProperty as the backing store for Hwnd.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty HandleProperty =
            DependencyProperty.Register("Handle", typeof(IntPtr), typeof(HwndSourceHost), new PropertyMetadata(IntPtr.Zero));
        HwndSource _source;
        protected override HandleRef BuildWindowCore(HandleRef hwndParent)
        {
            _source = new HwndSource(0, WS_CHILD | WS_VISIBLE | LBS_NOTIFY| WS_CLIPSIBLINGS, 0, 0, 0, (int)Width, (int)Height, "nativeHost", hwndParent.Handle);
            Handle = _source.Handle;
            return new HandleRef(this, Handle);
        }
        protected override void DestroyWindowCore(HandleRef hwnd)
        {
            _source.Dispose();
        }
        const int WS_CHILD = 0x40000000;
        const int WS_VISIBLE = 0x10000000;
        const int LBS_NOTIFY = 0x001;
        const int WS_CLIPSIBLINGS = 0x04000000;
    }
}

3、Wpf窗口

wpf窗口也可以进行嵌入，但需要导入win32对窗口属性进行设置，要设置WS_CHILD 以及父窗口。

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

namespace WpfHwndElement
{   
    //重新定义Handle为依赖属性，可以用于绑定
    public class WpfWindowHost : HwndHost
    {
        new public IntPtr Handle
        {
            get { return (IntPtr)GetValue(HandleProperty); }
            private set { SetValue(HandleProperty, value); }
        }
        // Using a DependencyProperty as the backing store for Hwnd.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty HandleProperty =
            DependencyProperty.Register("Handle", typeof(IntPtr), typeof(WpfWindowHost), new PropertyMetadata(IntPtr.Zero));
        const int WS_CHILD = 0x40000000;
        const int GWL_STYLE = (-16);
        [DllImport("user32.dll", EntryPoint = "GetWindowLongW")]
        static extern int GetWindowLong(IntPtr hwnd, int nIndex);
        [DllImport("user32.dll", EntryPoint = "SetWindowLongW")]
        static extern int SetWindowLong(IntPtr hwnd, int nIndex, int dwNewLong);
        [DllImport("user32.dll")]
        public static extern IntPtr SetParent(IntPtr hWndChild, IntPtr hWndNewParent);
        protected override HandleRef BuildWindowCore(HandleRef hwndParent)
        {
            var window = new Window();   
            var hwnd = new WindowInteropHelper(window).EnsureHandle();
            window.Show();
            SetWindowLong(hwnd, GWL_STYLE, GetWindowLong(hwnd, GWL_STYLE) | WS_CHILD);
            SetParent(hwnd, hwndParent.Handle);
            return new HandleRef(this, hwnd);
        }

        protected override void DestroyWindowCore(HandleRef hwnd)
        {
            var window = HwndSource.FromHwnd(hwnd.Handle)?.RootVisual as Window;
            window?.Close();
        }
    }
}

三、使用示例

MainWindow.xaml

<Window x:Class="WpfHwndElement.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:WpfHwndElement"
        mc:Ignorable="d"
        Title="MainWindow" Height="360" Width="640"   
        >
    <StackPanel>
        <local:Win32WindowHost Width="100" Height="100"/>
        <local:HwndSourceHost Margin="0,10,0,0" Width="100" Height="100"/>
        <local:WpfWindowHost Margin="0,10,0,0" Width="100" Height="100"/>
    </StackPanel>
</Window>

效果预览

总结

通过HwndHost的方式嵌入hwnd窗口是比较简单易用的，而且也为wpf实现的界面效果提供的更多的可能性，当然嵌入的窗口会覆盖wpf控件，虽然有解决的方法，本文主要还是提供基础的HwndHost用法。

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