在C#里调用vc写的动态连接库 下面几个函数 怎么在c#里声明调用 高分求助！！！

[king8192]

动态链接库名字为ext.dll
vc函数如下：

void WINAPI D_SetWorkMode(WORD wChnlNo,char cbWorkMode,char cbModeVal);

void WINAPI StartPlay ( WORD wChnlNo, char *PlayBuf, DWORD dwStartPos, DWORD dwPlayLen);

BOOL WINAPI StartPlayFile ( WORD wChnlNo, LPSTR FileName, DWORD StartPos );

void WINAPI StartPlayIndex( WORD wChnlNo, WORD *pIndexTable, WORD wIndexLen);

int WINAPI SetSendPara ( int ToneLen, int SilenceLen );

int WINAPI PcmtoWave(char* PcmFileName,char* WaveFileName);

int WINAPI DJFsk_SendFSK(int trunkID,BYTE* pInfo,WORD wSize,int Mode);

int WINAPI SetGenerateSigParam(int nSigType, int nFreq1, int nFreq2, double dbAmp1, double dbAmp2, int nOnTime, int nOffTime, int iSampleRate)

请在C#中正确声明调用，高分求助，谢谢！！

[onlinegame2007]

void    WINAPI D_SetWorkMode(WORD wChnlNo,char cbWorkMode,char  cbModeVal); 
        //这个是调用系统的动态链接库，如果是.NET平台的可以直接添加引用
        [DllImport("ext.dll")]
        public static extern void D_SetWorkMode(WORD wChnlNo,char cbWorkMode,char  cbModeVal); 

[onlinegame2007]

错了~~~~~~~~~

       //这个是调用系统的动态链接库，如果是.NET平台的可以直接添加引用
        [DllImport("ext.dll")]
        public static extern void D_SetWorkMode(WORD wChnlNo,char cbWorkMode,char  cbModeVal); 

[commandos]

c#声明如下：

void    int D_SetWorkMode(ushort wChnlNo,char cbWorkMode,char  cbModeVal); 

void    int StartPlay ( ushort wChnlNo, string PlayBuf, ulong dwStartPos, ulong dwPlayLen); 

bool    int StartPlayFile ( ushort wChnlNo, ref string FileName, ulong StartPos ); 

void    int StartPlayIndex( ushort wChnlNo, ref ushort pIndexTable, ushort wIndexLen); 

int     int SetSendPara ( int ToneLen, int SilenceLen ); 

int     int PcmtoWave(string PcmFileName,string WaveFileName); 

int     int DJFsk_SendFSK(int trunkID,ref byte pInfo,ushort wSize,int Mode); 

int     int SetGenerateSigParam(int nSigType, int nFreq1, int nFreq2, double dbAmp1, double dbAmp2, int nOnTime, int nOffTime, int iSampleRate) 

[tanguixing]

不知道在哪里定义?