将 c# 字符串传递给非托管 c++ DLL

Question

我有一个简单的应用程序，它加载一个非托管 dll 并从 C# 向它传递一些字符串值。但在 C++ dll 应用程序中，我收到异常 :: 试图访问读/写保护的内存。我的 DLL 导入看起来像这样：

[DllImport("X.dll", CallingConvention = CallingConvention.Cdecl) ]
public static extern int
DumpToDBLogFile([MarshalAs(UnmanagedType.I4)]int loggingLevel,
                [MarshalAs(UnmanagedType.I4)]int jobId,
                int threadId,
                [MarshalAs(UnmanagedType.LPStr)]string procName,
                [MarshalAs(UnmanagedType.LPStr)]string message);

C++ 声明就像

extern "C"    
__declspec(dllexport) int DumpToDBLogFile( int loggingLevel, int jobId, int threadId, string procName, string message )
{
    //access strings..
}

Help please!!!

Answer 1

string != LPStr

尝试：

extern "C"
__declspec(dllexport) int DumpToDBLogFile( int loggingLevel, int jobId, int threadId, char* procName, char* message ) { //access strings..

}

Answer 2

我将修改 pinvoke 签名......

[DllImport("X.dll", CallingConvention = CallingConvention.Cdecl) ]
public static extern int
DumpToDBLogFile(int loggingLevel, int jobId, int threadId, StringBuilder procName, StringBuilder message);

并从托管端使用初始化的 StringBuilder 类......

StringBuilder sbProcName = new StringBuilder(1024);
StringBuilder sbMessage = new StringBuilder(1024);

然后将 sbProcName 和 sbMessage 传递给 DumpToDBLogFile...

希望这有帮助，
此致，
汤姆.