Marshall结构通过sendmessage将其传递给delphi记录

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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);
    }
}

}

答案

您的代码中的一些小错误:

  • 你对COPYDATASTRUCT的定义缺少[StructLayout]
  • 你对SendMessage()的定义有点不对(wParam需要是UIntPtr而不是Int32)。
  • 你没有释放你用IntPtrAlloc()分配的任何内存。

现在,主要问题:

在将字符串编组为固定长度字符数组时,需要使用UnmanagedType.ByValTStr而不是UnmanagedType.LPTStr(请参阅Strings Used In Structures)。

但是,更重要的是(基于你在评论中提供的细节而不是在你的主要问题中),Delphi方面期望接收结构中的字符串以Short String格式编码,这与原始字符数组略有不同:

ShortString长度为0到255个单字节字符。虽然ShortString的长度可以动态改变,但它的内存是静态分配的256个字节;第一个字节存储字符串的长度,剩余的255个字节可用于字符。如果SShortString变量,Ord(S[0]),如Length(S),返回S的长度;为S[0]赋值,就像调用SetLength一样,改变了S的长度。 ShortString仅用于向后兼容。

Delphi语言支持短字符串类型 - 实际上是ShortString的子类型 - 其最大长度为0到255个字符。这些由附加在保留字string上的括号内数字表示。例如:

var MyString: string[100];

创建一个名为MyString的变量,其最大长度为100个字符。这相当于声明:

type CString = string[100];
var MyString: CString;

以这种方式声明的变量仅分配与类型所需的内存一样多 - 即指定的最大长度加上一个字节。在我们的示例中,MyString使用101个字节,而预定义的ShortString类型的变量则使用256个字节。

为短字符串变量赋值时,如果字符串超出该类型的最大长度,则会截断该字符串。

标准函数HighLow对短字符串类型标识符和变量进行操作。 High返回短字符串类型的最大长度,而Low返回零。

所以,尝试更像这样的东西:

[StructLayout(LayoutKind.Sequential)]
public struct COPYDATASTRUCT
{
    public IntPtr dwData;
    public int cbData;
    public IntPtr lpData;
}

[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi, Pack = 1)]
public struct ReturnStruct
{
    public int i;

    public byte card_len;
    [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 50)]
    public string card;

    public byte name_len;
    [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 100)]
    public string name;

    public byte responsecode_len;
    [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 5)]
    public string responsecode;

    public byte responsetext_len;
    [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 100)]
    public string responsetext;

    public byte approval_len;
    [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 15)]
    public string approval;

    public byte tranid_len;
    [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 50)]
    public string tranid;

    public byte reference_len;
    [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 16)]
    public string reference;

    public double d;

    public byte transactionType_len;
    [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 24)]
    public string transactionType;

    public byte creditCardType_len;
    [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 10)]
    public string creditCardType;

    public int EMVContact;

    public byte applicationName_len;
    [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 50)]
    public string applicationName;

    public byte applicationIdentifier_len;
    [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 15)]
    public string applicationIdentifier;

    public byte reserved_len;
    [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 10)]
    public string reserved;
}

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

    ret.i = ...;

    ret.card = ...;
    ret.card_len = (byte) Math.Min(System.Text.Encoding.Default.GetByteCount(ret.card), 50);

    ret.name = ...;
    ret.name_len = (byte) Math.Min(System.Text.Encoding.Default.GetByteCount(ret.name), 100);

    ret.responsecode = ...;
    ret.responsecode_len = (byte) Math.Min(System.Text.Encoding.Default.GetByteCount(ret.responsecode), 5);

    ret.responsetext = ...;
    ret.responsetext_len = (byte) Math.Min(System.Text.Encoding.Default.GetByteCount(ret.responsetext), 100);

    ret.approval = ...;
    ret.approval_len = (byte) Math.Min(System.Text.Encoding.Default.GetByteCount(ret.approval), 15);

    ret.tranid = ...;
    ret.tranid_len = (byte) Math.Min(System.Text.Encoding.Default.GetByteCount(ret.tranid), 50);

    ret.reference = ...;
    ret.reference_len = (byte) Math.Min(System.Text.Encoding.Default.GetByteCount(ret.reference), 16);

    ret.d = ...;

    ret.transactionType = ...;
    ret.transactionType_len = (byte) Math.Min(System.Text.Encoding.Default.GetByteCount(ret.transactionType), 24);

    ret.creditCardType = ...;
    ret.creditCardType_len = (byte) Math.Min(System.Text.Encoding.Default.GetByteCount(ret.creditCardType), 10);

    ret.EMVContact = ...;

    ret.applicationName = ...;
    ret.applicationName_len = (byte) Math.Min(System.Text.Encoding.Default.GetByteCount(ret.applicationName), 50);

    ret.applicationIdentifier = ...;
    ret.applicationIdentifier_len = (byte) Math.Min(System.Text.Encoding.Default.GetByteCount(ret.applicationIdentifier), 15);

    ret.reserved = ...;
    ret.reserved_len = (byte) Math.Min(System.Text.Encoding.Default.GetByteCount(ret.reserved), 10);

    return ret;
}

public static IntPtr IntPtrAlloc<T>(T param)
{
    IntPtr retval = Marshal.AllocHGlobal(Marshal.SizeOf(param));
    Marshal.StructureToPtr(param, retval, false);
    return retval;
}

public static void IntPtrFree(ref IntPtr preAllocated)
{
    Marshal.FreeHGlobal(preAllocated);
    preAllocated = IntPtr.Zero;
}

[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = false)]
public static extern int SendMessage(IntPtr hWnd, int uMsg, UIntPtr wParam, IntPtr lParam);

public void SendFingerPrintResult(string msg)
{ 
    // get the window to send struct
    IntPtr receiverHandle = GetWindow();
    if (receiverHandle == IntPtr.Zero) return;

    // Get the struct
    ReturnStruct ret = GetReturnStruct();
    IntPtr ptr = IntPtrAlloc(ret);
    try
    {
        var cds = new COPYDATASTRUCT
        {
            dwData = IntPtr.Zero,
            cbData = Marshal.SizeOf(ret),
            lpData = ptr
        };

        IntPtr iPtr = IntPtrAlloc(cds);
        try
        {
            SendMessage(receiverHandle, WM_COPYDATA, senderID, iPtr);
        }
        finally
        {
            IntPtrFree(ref iPtr);
        }
    }
    finally
    {
        IntPtrFree(ref ptr);
    }
}

您可以选择通过调整IntPtrAlloc()定义来删除内部SendMessage()调用(请参阅C# using SendMessage, problem with WM_COPYDATA):

[DllImport("user32.dll", CharSet = CharSet.Auto, EntryPoint = "SendMessage", SetLastError = false)]
public static extern int SendMessageCopyData(IntPtr hWnd, int uMsg, UIntPtr wParam, ref COPYDATASTRUCT lParam);

public void SendFingerPrintResult(string msg)
{ 
    // get the window to send struct
    IntPtr receiverHandle = GetWindow();
    if (receiverHandle == IntPtr.Zero) return;

    // Get the struct
    ReturnStruct ret = GetReturnStruct();
    IntPtr ptr = IntPtrAlloc(ret);
    try
    {
    

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