通过 WPF 中的 wndProc 与另一个进程（相同的源代码）通信

Question

我正在通过 WPF 中的HwndSource 实现与另一个进程的通信。

我希望我的程序（我们称之为 A）与 Windows 上另一个进程上的我的程序（也称为 A）进行通信。
下面的图片将帮助我解释我一直在做什么以及我想要实现什么。

两个窗口是完全相同的程序（只是背景颜色不同），并且它们彼此完全知道它们的句柄。如果我注意到两个进程具有相同的标题，那么我调用 sendMessage，它在 user32.dll 中定义，带有 Message -Raw 输入消息常量，可以全局泵送消息 -0x0100WM_KEYDOWN。

// if same program - but different process
IntPtr lpData = Marshal.StringToHGlobalAnsi("Hi, Im Sender");
MessageBox.Show(Marshal.PtrToStringAnsi(lpData));
DisplayAnotherProcessHandle.Text = p.MainWindowHandle.ToString();

SendMessage(p.MainWindowHandle, WM_RawInput_key, IntPtr.Zero, lpData);

我成功地将WM_RawInput_Key、IntPtr.Zero传递给对手程序。但我对 lParam 有疑问。我无法获取 lParam 数据。我试图用Marshal.StringToBSTR 或Marshal.StringToAuto 来编组c# string ...但在下面的方法中我只得到Empty.String。

private IntPtr WndProc(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled)
{
  if (msg != WM_RawInput_key) return IntPtr.Zero;

  if (wParam == IntPtr.Zero)  // <-- opponent process hit this conditional syntax nicely.
  {
    var str = Marshal.PtrToStringAnsi(lParam);  // but I'm failed pass lParam, or Marshalling lParam I don't know ...
    MessageBox.Show(str);
    DisplaySucceedOrNot.Text = str;
  }

  return IntPtr.Zero;
}

不知道IntPtr lParam表示的是哪个内存参数。我什至不知道这种技术是否有效。我需要你的帮助。感谢阅读

以下源代码是我的示例程序的完整源代码。

<Window x:Class="wndProc_IPC_WPF.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:wndProc_IPC_WPF"
        mc:Ignorable="d"
        Title="WndProc-IPC-WPF" Height="450" Width="800">
    <StackPanel>
        <Button Name="AddHandler" Width="Auto" Height="100" Content="Add Handler to This Handle" Click="AddHandler_Click"></Button>
        <Button Name="CreateNewProcess" Width="Auto" Height="100" Content="Create New Process Window" Click="CreateNewProcess_Click"></Button>
        <Button Width="Auto" Height="100" Content="SendMessage To Another Process" Name="SendMessageBtn" Click="SendMessage_Click"></Button>
        <StackPanel Orientation="Horizontal">
            <TextBlock Text="MyHandle : "></TextBlock>
            <TextBlock x:Name="DisplayMyProcessHandle" Margin="50 0 0 0"></TextBlock>
        </StackPanel>
        <StackPanel Orientation="Horizontal">
            <TextBlock Text="Another Handle : "></TextBlock>
            <TextBlock x:Name="DisplayAnotherProcessHandle" Margin="50 0 0 0"></TextBlock>
        </StackPanel>
        <StackPanel Orientation="Horizontal">
            <TextBlock Text="Succed?"></TextBlock>
            <TextBlock x:Name="DisplaySucceedOrNot" Margin="50 0 0 0"></TextBlock>
        </StackPanel>

    </StackPanel>
</Window>

public partial class MainWindow : Window
{
    [DllImport("user32.dll")]
    private static extern bool SendMessage(IntPtr hWnd, UInt32 Msg, IntPtr wParam, IntPtr lParam);

    string AppName;
    public static UInt32 WM_RawInput_key = 0x0100;

    public MainWindow()
    {
        InitializeComponent();
        AppName = this.Title;
    }

    private IntPtr WndProc(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled)
    {
        if (msg != WM_RawInput_key) return IntPtr.Zero;

        if (wParam == IntPtr.Zero)
        {
            var str = Marshal.PtrToStringAnsi(lParam);
            MessageBox.Show(str);
            DisplaySucceedOrNot.Text = str;
        }

        return IntPtr.Zero;
    }

    private void CreateNewProcess_Click(object sender, RoutedEventArgs e)
    {
        if (Process.GetProcessesByName(AppName).Length > 1)
        {
            MessageBox.Show("Already 2 Process Exist.");
            return;
        }
        var path = (System.Reflection.Assembly.GetExecutingAssembly().GetName().CodeBase);
        Process p = new Process();
        p.StartInfo.FileName = path;
        p.Start();
    }

    private void SendMessage_Click(object sender, RoutedEventArgs e)
    {
        foreach (var p in Process.GetProcessesByName(AppName))
        {
            if (p.MainWindowHandle == Process.GetCurrentProcess().MainWindowHandle) continue; 

            {
                IntPtr lpData = Marshal.StringToHGlobalAnsi("Hi, Im Sender");
                MessageBox.Show(Marshal.PtrToStringAnsi(lpData));
                DisplayAnotherProcessHandle.Text = p.MainWindowHandle.ToString();

                SendMessage(p.MainWindowHandle, WM_RawInput_key, IntPtr.Zero, lpData);

            }
        }
    }

    private void AddHandler_Click(object sender, RoutedEventArgs e)
    {
        HwndSource source = HwndSource.FromHwnd(Process.GetCurrentProcess().MainWindowHandle);
        source.AddHook(new HwndSourceHook(WndProc));
    }

}

Answer 1

wparam 和lparam 只是指向本地进程内存的指针，其他进程无法访问。 wparam 在您的示例中运行良好，因为您只处理指针值而不是它指向的数据。

出于类似目的，我使用了WM_COPYDATA 消息，您提供了指向COPYDATASTRUCT 的指针。在那里，您还可以封装复杂的数据结构，这些数据结构可以在您的接收过程中以只读方式处理。

Microsoft 在这里提供了一个有用的示例： https://docs.microsoft.com/en-us/windows/win32/dataxchg/using-data-copy

Answer 2

谢谢 Mihaeru，实际上我是在发布我的问题后在 Wpf 中寻找 sendMessage/wndProc 和 WM_COPYDATA 的示例来源。像 Raw-Input 消息WM_KEYDOWN，WM_COPYDATA 也提供全局消息泵（对吗？，我不知道旧窗口的确切理论...-_-;;）

我失败了很多次。我发现我应该用字符串长度分配cbData。如果我添加属性 [MarshalAs(UnmanagedType.LpWStr)] 每个字符 2 个字节，那么我需要将 string.length*2 分配给 cbData。

我成功将消息传递给对方进程。

以下来源是答案来源

        [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi)]
        public struct COPYDATASTRUCT
        {
            public IntPtr dwData;
            public int cbData;
            [MarshalAs(UnmanagedType.LPStr)]
            public string lpData;
        }

        [DllImport("user32.dll")]
        private static extern bool SendMessage(IntPtr hWnd, UInt32 Msg, IntPtr wParam, ref COPYDATASTRUCT lParam);

        string AppName;
        public static UInt32 WM_COPYDATA = 0x004A;

        public MainWindow()
        {
            InitializeComponent();
            AppName = this.Title;
        }

        private IntPtr WndProc(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled)
        {
            if (msg != WM_COPYDATA) return IntPtr.Zero;

            if (wParam == IntPtr.Zero)
            {

                COPYDATASTRUCT cd = new COPYDATASTRUCT();
                cd = (COPYDATASTRUCT)Marshal.PtrToStructure(lParam, typeof(COPYDATASTRUCT));
                MessageBox.Show(cd.lpData);
                DisplaySucceedOrNot.Text = cd.lpData;
            }
            return IntPtr.Zero;
        }

        private void CreateNewProcess_Click(object sender, RoutedEventArgs e)
        {
            if (Process.GetProcessesByName(AppName).Length > 1)
            {
                MessageBox.Show("Already 2 Process Exist.");
                return;
            }
            var path = (System.Reflection.Assembly.GetExecutingAssembly().GetName().CodeBase);
            Process p = new Process();
            p.StartInfo.FileName = path;
            p.Start();
        }

        private void SendMessage_Click(object sender, RoutedEventArgs e)
        {
            foreach (var p in Process.GetProcessesByName(AppName))
            {
                if (p.MainWindowHandle == Process.GetCurrentProcess().MainWindowHandle) continue;

                {
                    IntPtr lpData = Marshal.StringToHGlobalAnsi("Hi, Im Sender");

                    COPYDATASTRUCT cd = new COPYDATASTRUCT();
                    cd.lpData = "Hi, Im Sender";
                    cd.dwData = p.MainWindowHandle;
                    cd.cbData = cd.lpData.Length+1;

                    MessageBox.Show(cd.lpData);
                    DisplayAnotherProcessHandle.Text = p.MainWindowHandle.ToString();
                    SendMessage(p.MainWindowHandle, WM_COPYDATA, IntPtr.Zero, ref cd);
                }
            }
        }

        private void AddHandler_Click(object sender, RoutedEventArgs e)
        {
            HwndSource source = HwndSource.FromHwnd(Process.GetCurrentProcess().MainWindowHandle);

            source.AddHook(new HwndSourceHook(WndProc));
            DisplayMyProcessHandle.Text = Process.GetCurrentProcess().MainWindowHandle.ToString();
        }