将c#字符串传递给非托管的c++ DLL

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:

我有一个简单的应用程序，它加载一个非托管的dll并从c#中传递一些字符串值给它。但是在c++ dll应用程序中，我收到一个异常::尝试访问一个读/写保护内存。我的DLL导入是这样的:

[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

c++声明是这样的

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

Help please!!!

请帮助! ! !

2 个解决方案

#1

string != LPStr

try:

试一试:

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

}

#2

I would modify the pinvoke signature....

段我将修改pinvoke签名....

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

And from the managed side use the StringBuilder class initialized....

从管理方面使用StringBuilder类初始化....

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

Then pass in the sbProcName and sbMessage to the DumpToDBLogFile...

然后将sbProcName和sbMessage传递给DumpToDBLogFile…

Hope this helps, Best regards, Tom.

祝你好运，汤姆。

#1

string != LPStr