Marshall结构通过sendmessage将其传递给delphi记录

Question

我试图通过c＃将结构传递给delphi，我已经完成了以下传递消息，我按照pinvoke的格式从https://www.pinvoke.net/default.aspx/Structures.COPYDATASTRUCT复制datat结构，但在delphi上我没有收到任何消息。在某种程度上，我认为这是因为我没有以正确的方式编码结构。当我只传递一个字符串消息时，我会收到它，但是当我尝试传递结构时，什么都没有

这就是我到目前为止所做的。

using System;

using System.Runtime.InteropServices;

using System.Windows.Forms;

namespace ccTestForm2
{
public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
        SendFingerPrintResult();
    }
    const int WM_COPYDATA = 0x004A;
    //include SendMessage
    [DllImport("user32.dll")]
    public static extern IntPtr FindWindow(string lpszClass, string 
  lpszWindow);
    [DllImport("user32.dll", CharSet = CharSet.Ansi, EntryPoint = "SendMessage", SetLastError = false)]
    public static extern int SendMessageCopyData(IntPtr hWnd, int uMsg, UIntPtr wParam, ref COPYDATASTRUCT lParam);
    [StructLayout(LayoutKind.Sequential)]
    public struct COPYDATASTRUCT
    {
        public IntPtr dwData;
        public int cbData;
        public IntPtr lpData;
    }

    public struct ReturnStruct
    {
        public int i;
        public string card;
        public string name;
        public string responsecode;
        public string responsetext;
        public string approval;
        public string tranid;
        public string reference;
        public double d;
        public string transactionType;
        public string creditCardType;
        public int EMVContact;
        public string applicationName;
        public string applicationIdentifier;
        public string reserved;

        public IntPtr ToPtr()
        {
            IntPtr ret = Marshal.AllocHGlobal(473);

            IntPtr ptr = ret;
            Marshal.WriteInt32(ptr, i); ptr = IntPtr.Add(ptr, 4);
            DelphiShortStringHelper.WriteToPtr(card, ref ptr, 50);
            DelphiShortStringHelper.WriteToPtr(name, ref ptr, 100);
            DelphiShortStringHelper.WriteToPtr(responsecode, ref ptr, 5);
            DelphiShortStringHelper.WriteToPtr(responsetext, ref ptr, 100);
            DelphiShortStringHelper.WriteToPtr(approval, ref ptr, 15);
            DelphiShortStringHelper.WriteToPtr(tranid, ref ptr, 50);
            DelphiShortStringHelper.WriteToPtr(reference, ref ptr, 16);
            Marshal.Copy(new double[] { d }, 0, ptr, 1); ptr = IntPtr.Add(ptr, 8);
            DelphiShortStringHelper.WriteToPtr(transactionType, ref ptr, 24);
            DelphiShortStringHelper.WriteToPtr(creditCardType, ref ptr, 10);
            Marshal.WriteInt32(ptr, EMVContact); ptr = IntPtr.Add(ptr, 4);
            DelphiShortStringHelper.WriteToPtr(applicationName, ref ptr, 50);
            DelphiShortStringHelper.WriteToPtr(applicationIdentifier, ref ptr, 15);
            DelphiShortStringHelper.WriteToPtr(reserved, ref ptr, 10);

            return ret;
        }
    }

    public ReturnStruct GetReturnStruct()
    {
        var ret = new ReturnStruct();

        ret.i = 2;

        ret.card = "1234";

        ret.name = "test";

        ret.responsecode = "mese";

        ret.responsetext = "dork";

        ret.approval = "Plerk";


        ret.tranid = "pse";

        ret.reference = "Ig";


        ret.d = DateTime.UtcNow.ToOADate();

        ret.transactionType = "cit";


        ret.creditCardType = "t2";


        ret.EMVContact = 0;

        ret.applicationName = "mpp";


        ret.applicationIdentifier = "nne";


        ret.reserved = "12";

        return ret;
    }

    public void SendFingerPrintResult()
    {
        // get the window to send struct
        IntPtr receiverHandle = FindWindow("TReceiverMainForm", "ReceiverMainForm");
        if (receiverHandle == IntPtr.Zero) return;

        // Get the struct
        ReturnStruct ret = GetReturnStruct();
        IntPtr ptr = ret.ToPtr();
        try
        {
            var cds = new COPYDATASTRUCT
            {
                dwData = IntPtr(2), // to identify the message contents
                cbData = Marshal.SizeOf(ret),
                lpData = ptr
            };
            SendMessageCopyData(receiverHandle, WM_COPYDATA, UIntPtr.Zero, ref cds);
        }
        finally
        {
            Marshal.FreeHGlobal(ptr);
        }
    }
}
class DelphiShortStringHelper
{
    public static void WriteToPtr(string s, ref IntPtr ptr, byte maxChars = 255)
    {
        byte[] bytes = System.Text.Encoding.Default.GetBytes(s);
        int strLen = Math.Min(bytes.Length, (int)maxChars);
        Marshal.WriteByte(ptr, (byte)strLen);
        ptr = IntPtr.Add(ptr, 1);
        Marshal.Copy(bytes, 0, ptr, strLen);
        ptr = IntPtr.Add(ptr, (int)maxChars);
    }
}

}