传递C＃字符串非托管C ++ DLL [英] Passing c# string to unmanaged c++ DLL

问题描述

我有一个简单的应用程序加载的非托管的DLL，并传递了一些字符串值，将它从C＃。但在C ++ DLL的应用程序，我收到一个异常：试图访问一个读/写保护的内存。我的DLL导入是这样的：

  [的DllImport（X.dll，CallingConvention = CallingConvention.Cdecl）
公共静态外部INT
DumpToDBLogFile（[的MarshalAs（UnmanagedType.I4）INT loggingLevel，
                [的MarshalAs（UnmanagedType.I4）INT JOBID，
                INT threadId的，
                [的MarshalAs（UnmanagedType.LPStr）字符串PROCNAME，
                [的MarshalAs（UnmanagedType.LPStr）字符串消息）;
 

和C ++的宣言就像

 的externC
__declspec（dllexport）的INT DumpToDBLogFile（INT loggingLevel，诠释JOBID，诠释threadId的，串PROCNAME，字符串消息）
{
    //访问字符串..
}
 

请帮助！

解决方案

 字符串！= LPSTR
 

尝试：

 的externC
__declspec（dllexport）的INT DumpToDBLogFile（INT loggingLevel，诠释JOBID，诠释threadId的，字符* PROCNAME，字符*消息）{//访问字符串..

}
 

I have a simple application that loads an unmanaged dll and passes a few string values to it from C#. But in the C++ dll application, I receive an exception :: Tried to access a read/write protected memory. My DLL Import looks like this:

[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);

and the C++ Declaration is like

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

Help please!!!

解决方案

string != LPStr

try:

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

}

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