Unity3D界面嵌入WPF界面中（鼠标键盘均可正常响应）

1、引用System.Windows.Forms.dll和WindowsFormsIntegration.dll

unity3D界面不能够直接嵌入到WPF控件中，但是可以嵌入到WinForm控件中，所以我们需要在WPF中使用WinForm控件作为载体。需要引用上述dll，如下图所示：

然后在Xaml文件中引入命名空间即可使用WinForm控件，例如：

xmlns:wf="clr-namespace:System.Windows.Forms;assembly=System.Windows.Forms"
<WindowsFormsHost Grid.Row="1">
    <wf:Panel/>
</WindowsFormsHost>

2、将Unity3d嵌入到WinForm控件中

public class AppContainer
    {
        private System.Windows.Forms.Panel _hostPanel;
        private readonly ManualResetEvent _eventDone = new ManualResetEvent(false);
        private Process _process = null;
        internal IntPtr _embededWindowHandle;

        public AppContainer(System.Windows.Forms.Panel panel)
        {
            this._hostPanel = panel;
            this._hostPanel.Resize += _hostPanel_Resize;
        }


        private void _hostPanel_Resize(object sender, EventArgs e)
        {
            SetBounds();
        }

        public void ActivateWindow()
        {
            if (_process == null)
                return;

            if (_process.MainWindowHandle == IntPtr.Zero)
                return;

            Win32Api.SendMessage(_process.MainWindowHandle, Win32Api.WM_ACTIVATE, Win32Api.WA_ACTIVE, IntPtr.Zero);
        }

        public void SetBounds()
        {
            SetBounds(_hostPanel.Width, _hostPanel.Height);
        }

        public void SetBounds(int width, int height)
        {
            if (_process == null)
                return;

            if (_process.MainWindowHandle == IntPtr.Zero)
                return;

            if (width <= 0 || height <= 0)
                return;

            Win32Api.MoveWindow(_process.MainWindowHandle, 0, 0, width, height, true);

            ActivateWindow();//激活
        }

        public bool StartAndEmbedProcess(string processPath)
        {
            if (null != _process)
                return true;

            var isStartAndEmbedSuccess = false;
            _eventDone.Reset();

            // Start the process 
            ProcessStartInfo info = new ProcessStartInfo(processPath);
            info.WindowStyle = ProcessWindowStyle.Maximized;//默认最大化，不弹出界面。
            info.Arguments = $"-popupwindow";//Unity的命令行参数

            _process = Process.Start(info);

            if (_process == null)
            {
                return false;
            }

            // Wait for process to be created and enter idle condition 
            _process.WaitForInputIdle();

            // Get the main handle
            var thread = new Thread(() =>
            {
                while (true)
                {
                    if (_process.MainWindowHandle != (IntPtr)0)
                    {
                        _eventDone.Set();
                        break;
                    }
                    Thread.Sleep(10);
                }
            });
            thread.Start();

            //嵌入进程
            if (_eventDone.WaitOne(10000))
            {
                isStartAndEmbedSuccess = EmbedApp(_process);
                if (!isStartAndEmbedSuccess)
                {
                    CloseApp(_process);
                }
            }
            return isStartAndEmbedSuccess;
        }

        public bool EmbedExistProcess(Process process)
        {
            _process = process;
            return EmbedApp(process);
        }

        /// <summary>
        /// 将外进程嵌入到当前程序
        /// </summary>
        /// <param name="process"></param>
        private bool EmbedApp(Process process)
        {
            //是否嵌入成功标志，用作返回值
            var isEmbedSuccess = false;
            //外进程句柄
            var processHwnd = process.MainWindowHandle;
            //容器句柄
            var panelHwnd = _hostPanel.Handle;

            if (processHwnd != (IntPtr)0 && panelHwnd != (IntPtr)0)
            {
                //把本窗口句柄与目标窗口句柄关联起来
                var setTime = 0;
                while (!isEmbedSuccess && setTime < 50)
                {
                    // Put it into this form
                    isEmbedSuccess = Win32Api.SetParent(processHwnd, panelHwnd) != 0;
                    Thread.Sleep(10);
                    setTime++;
                }

                // Remove border and whatnot
                //Win32Api.SetWindowLong(processHwnd, Win32Api.GWL_STYLE, Win32Api.WS_CHILDWINDOW | Win32Api.WS_CLIPSIBLINGS | Win32Api.WS_CLIPCHILDREN | Win32Api.WS_VISIBLE);

                SetBounds();

                 Move the window to overlay it on this window
                //Win32Api.MoveWindow(_process.MainWindowHandle, 0, 0, (int)ActualWidth, (int)ActualHeight, true);
            }

            if (isEmbedSuccess)
            {
                _embededWindowHandle = _process.MainWindowHandle;
            }

            return isEmbedSuccess;
        }

        /// <summary>
        /// 关闭进程
        /// </summary>
        /// <param name="process"></param>
        private void CloseApp(Process process)
        {
            if (process != null && !process.HasExited)
            {
                process.Kill();
            }
        }

        public void CloseProcess()
        {
            CloseApp(_process);
            _process = null;
        }
    }

这是一个嵌入的实例类，构造函数会把WinForm控件以参数的形式传入，然后此控件需要订阅Resize事件，该事件处理器进行了unity3D窗体的重新激活。

在进程启动的时候使用了命令行参数info.Arguments = $"-popupwindow";//Unity的命令行参数。

依然使用的Win32Api设置为父窗体， Win32Api.SetParent(processHwnd, panelHwnd)。

<Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="auto"/>
            <RowDefinition />
        </Grid.RowDefinitions>
       
        <Grid Grid.Row="0">
            <Button Margin="3" Content="Embed" Click="Button_Click" HorizontalAlignment="Center"/>
        </Grid>

        <WindowsFormsHost Grid.Row="1">
            <wf:Panel x:Name="host"/>
        </WindowsFormsHost>
    </Grid>

private void Button_Click(object sender, RoutedEventArgs e)
       {
           AppContainer container = new AppContainer(this.host);

           container.StartAndEmbedProcess(@"Child.exe");
       }

3、效果演示

鼠标和键盘均可正常响应。

4、.NetCore

目前很多项目使用的.NetCore，任何发现用不了上述说的dll。那么因为需要在项目文件中添加如下信息：

<PropertyGroup>
  <TargetFramework>netcoreapp3.1</TargetFramework>
  <UseWPF>true</UseWPF>
  <UseWindowsForms>true</UseWindowsForms>
  <AssemblyName>SIFP.Core</AssemblyName>
</PropertyGroup>

https://blog.csdn.net/zhudaokuan/article/details/109007012

5、补充win32api

public class Win32Api
    {
        [DllImport("User32.dll")]
        public static extern bool MoveWindow(IntPtr handle, int x, int y, int width, int height, bool redraw);

        internal delegate int WindowEnumProc(IntPtr hwnd, IntPtr lparam);
        [DllImport("user32.dll")]
        internal static extern bool EnumChildWindows(IntPtr hwnd, WindowEnumProc func, IntPtr lParam);

        [DllImport("user32.dll")]
        public static extern int SendMessage(IntPtr hWnd, int msg, IntPtr wParam, IntPtr lParam);

        [DllImport("user32.dll", SetLastError = true)]
        public static extern int SetParent(IntPtr hWndChild, IntPtr hWndNewParent);

        internal Process process;
        internal IntPtr unityHWND = IntPtr.Zero;

        internal const int WM_ACTIVATE = 0x0006;
        internal static readonly IntPtr WA_ACTIVE = new IntPtr(1);
        internal static readonly IntPtr WA_INACTIVE = new IntPtr(0);
    }