C# 使用SendMessage WM_COPYDATA发送双数组

我在将双数组从一个应用程序发送到另一个应用程序时遇到了问题

我尝试按如下方式格式化CopyData结构：

    [StructLayout(LayoutKind.Sequential)]
    public struct CopyDataStruct
    {
        public IntPtr dwData;
        public int cbData;
        [MarshalAs(UnmanagedType.ByValArray, ArraySubType = UnmanagedType.R8)]
        public double[] lpData;
    }

            double[] a = new double[2] { 1.0, 2.0 };
            int size = Marshal.SizeOf(typeof(double)) * a.Count();

            CopyDataStruct copyDataStruct;
            copyDataStruct.dwData = IntPtr.Zero;
            copyDataStruct.lpData = a;
            copyDataStruct.cbData = size;

            int result = SendMessage(hWnd, WM_COPYDATA, 0, ref copyDataStruct);

在Sender应用程序中，我按如下方式填充结构：

    [StructLayout(LayoutKind.Sequential)]
    public struct CopyDataStruct
    {
        public IntPtr dwData;
        public int cbData;
        [MarshalAs(UnmanagedType.ByValArray, ArraySubType = UnmanagedType.R8)]
        public double[] lpData;
    }

            double[] a = new double[2] { 1.0, 2.0 };
            int size = Marshal.SizeOf(typeof(double)) * a.Count();

            CopyDataStruct copyDataStruct;
            copyDataStruct.dwData = IntPtr.Zero;
            copyDataStruct.lpData = a;
            copyDataStruct.cbData = size;

            int result = SendMessage(hWnd, WM_COPYDATA, 0, ref copyDataStruct);

在接收器应用程序中，我尝试以下方法：

    private IntPtr WndProc(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled)
    {
        switch (msg)
        {
            case (int)WINMESSAGES.WM_COPYDATA:
                CopyDataStruct cp = (CopyDataStruct)Marshal.PtrToStructure(lParam, typeof(CopyDataStruct));

                break;
        }

        return IntPtr.Zero;
    }

---

但在cp.lpData中，值为空。我不知道我是发错了还是收错了。请帮助，谢谢。

您需要使用本机内存。像那样通过C双[]是行不通的。它将被垃圾收集，而且，它甚至没有在C中分配-它只是在堆栈中。您可以使用不安全/固定关键字锁定对象，也可以使用AllocHGlobal

这是我从互联网上窃取的一些代码。演示发送部分：

    // Marshal the managed struct to a native block of memory.
    var myStruct = new double[2] { 1.0, 2.0 };
    int myStructSize = Marshal.SizeOf(myStruct); 
    IntPtr pMyStruct = Marshal.AllocHGlobal(myStructSize);
    try
    {
        Marshal.StructureToPtr(myStruct, pMyStruct, true);

        COPYDATASTRUCT cds = new COPYDATASTRUCT();
        cds.cbData = myStructSize;
        cds.lpData = pMyStruct;

        // Send the COPYDATASTRUCT struct through the WM_COPYDATA message to 
        // the receiving window. (The application must use SendMessage, 
        // instead of PostMessage to send WM_COPYDATA because the receiving 
        // application must accept while it is guaranteed to be valid.)
        NativeMethod.SendMessage(hTargetWnd, WM_COPYDATA, this.Handle, ref cds);

        int result = Marshal.GetLastWin32Error();
        if (result != 0)
        {
            MessageBox.Show(String.Format(
                "SendMessage(WM_COPYDATA) failed w/err 0x{0:X}", result));
        }
    }
    finally
    {
        Marshal.FreeHGlobal(pMyStruct);
    }

---

take:

获取null很难解释，但它不能像声明的那样工作。PtrToStructure无法计算阵列的大小。将SizeConst=2添加到[Marshallas]属性，然后重试。谢谢。我尝试了这个方法，在Receiver中我得到了一个双数组，索引0 cp.lpData[0]=2.0760134663004284E-305中的数字非常低，索引1 cp.lpData[1]=6.6028210135419114E+260中的数字非常高。SendMessage的声明是错误的，第三个参数是IntPtr，而不是int。[DllImportUser32.dll，EntryPoint=SendMessage]公共静态外部int sendmagesint hWnd、int Msg、int wParam、ref CopyDataStruct lParam；这适用于个人价值观​​弦乐，双打。我不能让它只适用于阵列。再次谢谢你，汉斯。谢谢你的回答。在Marshal.structurettrmystruct中，pmystuct为true；我有一个错误，指定的结构必须是飞航或布局信息。有什么想法吗？