尝试读取或写入受保护的内存，这通常指示其他内存已损坏(急，online)

Question

类型是否正确
http://topic.csdn.net/u/20090522/20/ae470ef3-b964-4c45-aa89-4b07ae7b4ef6.html

Answer 1

char *的参数，如是传入，就用string，传出用StringBuilder,另外，CharSet = CharSet.Ansi或Auto

Answer 2

extern static int SMGPSendSingle(..., StringBuilder sMsgID, ref int nErrorCode);

Answer 3

/// Return Type: int
    ///nNeedReply: int
    ///nMsgLevel: int
    ///sServiceID: char*
    ///nMsgFormat: int
    ///sFeeType: char*
    ///sFeeCode: char*
    ///sValidTime: char*
    ///sAtTime: char*
    ///sChargeTermID: char*
    ///sDestTermID: char*
    ///sReplyPath: char*
    ///nMsgLen: int
    ///sMsgContent: char*
    ///sMsgID: char*
    ///nErrorCode: int*
    [System.Runtime.InteropServices.DllImportAttribute("<Unknown>", EntryPoint="SMGPSendSingle", CallingConvention=System.Runtime.InteropServices.CallingConvention.StdCall)]
public static extern  int SMGPSendSingle(int nNeedReply, int nMsgLevel, [System.Runtime.InteropServices.InAttribute()] [System.Runtime.InteropServices.MarshalAsAttribute(System.Runtime.InteropServices.UnmanagedType.LPStr)] string sServiceID, int nMsgFormat, [System.Runtime.InteropServices.InAttribute()] [System.Runtime.InteropServices.MarshalAsAttribute(System.Runtime.InteropServices.UnmanagedType.LPStr)] string sFeeType, [System.Runtime.InteropServices.InAttribute()] [System.Runtime.InteropServices.MarshalAsAttribute(System.Runtime.InteropServices.UnmanagedType.LPStr)] string sFeeCode, [System.Runtime.InteropServices.InAttribute()] [System.Runtime.InteropServices.MarshalAsAttribute(System.Runtime.InteropServices.UnmanagedType.LPStr)] string sValidTime, [System.Runtime.InteropServices.InAttribute()] [System.Runtime.InteropServices.MarshalAsAttribute(System.Runtime.InteropServices.UnmanagedType.LPStr)] string sAtTime, [System.Runtime.InteropServices.InAttribute()] [System.Runtime.InteropServices.MarshalAsAttribute(System.Runtime.InteropServices.UnmanagedType.LPStr)] string sChargeTermID, [System.Runtime.InteropServices.InAttribute()] [System.Runtime.InteropServices.MarshalAsAttribute(System.Runtime.InteropServices.UnmanagedType.LPStr)] string sDestTermID, [System.Runtime.InteropServices.InAttribute()] [System.Runtime.InteropServices.MarshalAsAttribute(System.Runtime.InteropServices.UnmanagedType.LPStr)] string sReplyPath, int nMsgLen, [System.Runtime.InteropServices.InAttribute()] [System.Runtime.InteropServices.MarshalAsAttribute(System.Runtime.InteropServices.UnmanagedType.LPStr)] string sMsgContent, System.IntPtr sMsgID, ref int nErrorCode) ;
sMsgID指向内存的所有权不明，暂时用System.IntPtr(也就是.Net里面的void*)列集。

Answer 4

如问题在 最后两个参数里面，最后两个参数都是需要修改值的所以char *sMsgID  = StringBuild sMsgID 
int *nErrorCode = ref int nErrorCode