将结构数组从 C#(.NET Core) 传递到 C++(unamnaged)

Question

所以我阅读了文档和无数在线示例，了解如何编组结构数组。我编组了 int 数组，编组了结构，但现在我完全卡住了，无论我尝试什么都无法让它工作。已经卡了一天多了。

Structure/class，两者都尝试过

    [StructLayout(LayoutKind.Sequential,CharSet = CharSet.Unicode)]
public class SaveDetails
{
    [MarshalAs(UnmanagedType.LPWStr)]
    public string Log;
    public FILETIME FileTime;
    [MarshalAs(UnmanagedType.Bool)]
    public bool Saved;
}

Pinvoke 并调用委托

public class LogSaveFiles : IDisposable
{
    [UnmanagedFunctionPointer(CallingConvention.Winapi,CharSet = CharSet.Unicode)]
    private delegate Status DLogSaveFiles([ In, Out] SaveDetails[] logsToSave, string destinationPath);
    private static DLogSaveFiles _dLogSaveFiles;

    private IntPtr PLogSaveFiles { get; set; }
    public bool LogSaveFilesAvailable => PLogSaveFiles != IntPtr.Zero;

    public LogSaveFiles(Importer importer)
    {
        if (importer.dllLibraryPtr!= IntPtr.Zero)
        {
            PLogSaveFiles = Importer.GetProcAddress(importer.dllLibrary, "LogSaveFiles");
        }
    }

    public Status SaveFiles(SaveDetails[] logsToSave,string destinationPath)
    {
        Status result = Status.FunctionNotAvailable;

        if (LogSaveFilesAvailable)
        {
            _dLogSaveFiles = (DLogSaveFiles)Marshal.GetDelegateForFunctionPointer(PLogSaveFiles, typeof(DLogSaveFiles));

            result = _dLogSaveFiles(logsToSave, destinationPath);
        }

        return result;
    }

    public void Dispose()
    {

    }
}

通话

      private void SaveLogs()
    {
        var logsToSave = new[]{
            new SaveDetails{
                FileTime = new FILETIME {dwHighDateTime = 3,dwLowDateTime = 5},
                Log = LogTypes.logDeviceLog,
                Saved = true},
            new SaveDetails{
                FileTime = new FILETIME {dwHighDateTime = 1,dwLowDateTime = 2},
                Log = LogTypes.logDeviceLog,
                Saved = false}
             };

        var pathToSave = "C:\Logs";
        _logSaveFiles.SaveFiles(logsToSave, pathToSave);
    }

c++ 公开调用

    typedef struct _LOG_SAVE_DETAILS
{
    LPTSTR      szLog;
    FILETIME    fromFileTime;
    BOOL        bSaved;
} LOG_SAVE_DETAILS, *PLOG_SAVE_DETAILS;


/* Function definitions */

ULY_STATUS _API LogSaveFiles (PLOG_SAVE_DETAILS   ppLogs [],
                                         LPCTSTR                szDestinationPath);

目标路径已正确传递，但结构数组从未通过，导致在尝试访问它时发生访问冲突。起初我以为是 LPTSTR 没有正常通过的问题，但我已经用它自己实现了其他调用并成功编组通过。

我在https://docs.microsoft.com/en-us/dotnet/framework/interop/marshaling-data-with-platform-invoke上看了所有内容，都表明我的做法是正确的，但行不通。

感谢任何帮助。

Answer 1

简单解决方案：C端将PLOG_SAVE_DETAILS ppLogs []改为LOG_SAVE_DETAILS ppLogs []，然后C#端将public class SaveDetails改为public struct SaveDetails。

编组对象数组似乎很困难（我没能做到）。编组结构数组有效。另一种方法是手动进行编组，但这很痛苦。

手动编组的"pain"（仅修改代码行）：

[UnmanagedFunctionPointer(CallingConvention.Winapi, CharSet = CharSet.Unicode)]
private delegate Status DLogSaveFiles(IntPtr[] logsToSave, string destinationPath);

然后

public Status SaveFiles(SaveDetails[] logsToSave, string destinationPath)
{
    Status result = Status.FunctionNotAvailable;

    if (LogSaveFilesAvailable)
    {
        if (_dLogSaveFiles == null)
        {
            _dLogSaveFiles = (DLogSaveFiles)Marshal.GetDelegateForFunctionPointer(PLogSaveFiles, typeof(DLogSaveFiles));
        }

        int size = Marshal.SizeOf(typeof(SaveDetails));

        IntPtr basePtr = IntPtr.Zero;
        IntPtr[] ptrs = new IntPtr[logsToSave.Length + 1];

        try
        {
            basePtr = Marshal.AllocHGlobal(size * logsToSave.Length);

            for (int i = 0; i < logsToSave.Length; i++)
            {
                ptrs[i] = IntPtr.Add(basePtr, (i * size));
                Marshal.StructureToPtr(logsToSave[i], ptrs[i], false);
            }

            result = _dLogSaveFiles(ptrs, destinationPath);
        }
        finally
        {
            if (basePtr != IntPtr.Zero)
            {
                for (int i = 0; i < logsToSave.Length; i++)
                {
                    if (ptrs[i] != IntPtr.Zero)
                    {
                        Marshal.DestroyStructure(ptrs[i], typeof(SaveDetails));
                    }
                }

                Marshal.FreeHGlobal(basePtr);
            }
        }
    }

    return result;
}

重要提示：这是一个封送拆收器 C#->C++。 C++ 不得以任何方式修改接收到的数组，否则会发生内存泄漏。

将结构数组从 C#(.NET Core) 传递到 C++(unamnaged)

Passing Array of Structures from C#(.NET Core) to C++(unamnaged)

c#

c++

pinvoke

marshalling

.net-core