C#怎么调用C++dll中带有回调函数的方法

[julia_ann]

C++中的函数为

int WINAPI ecwOpenCallback( ECW_CALLBACK fCallback,
const char *szSvrIP=NULL,
long nPort = 7901,
const char *szAppName=NULL);

回调函数声明如下

typedef long (__stdcall *ECW_CALLBACK)(WORD wEvent, WORD wIndex,const
LPECWATCHDATA lpecwData);

LPECWATCHDATA的定义为

typedef struct {
 WORD     nState;               //状态
 WORD     nIdx;                 //索引
 WORD     wDataCnt;             //数据(lpData)项数  
 char     szTime[20];           //时间
 char* lpIDString;     //设备号码
 char* lpNameString;   //设备/用户名称
 char* lpData[8];
}ECWATCHDATA,*LPECWATCHDATA;

我在C#中该怎么写？

[EnForGrass]

C#中可以用委托来实现 参考http://blog.csdn.net/songjinshi/article/details/8153635 http://blog.csdn.net/iamherego/article/details/50458984

[xian_wwq]

在c++/c中是回调，在c#中 对应的是委托 根据c++定义的类型对应定义 就可以了

[EnForGrass]

typedef long (__stdcall *ECW_CALLBACK)(WORD wEvent, WORD wIndex,const
LPECWATCHDATA lpecwData);

对应C#委托

[System.Runtime.InteropServices.UnmanagedFunctionPointerAttribute(System.Runtime.InteropServices.CallingConvention.StdCall)]
public delegate int ECW_CALLBACK(ushort wEvent, ushort wIndex, ref ECWATCHDATA lpecwData);

[EnForGrass]

再帮你把结构体用C#定义出来吧

[System.Runtime.InteropServices.StructLayoutAttribute(System.Runtime.InteropServices.LayoutKind.Sequential, CharSet=System.Runtime.InteropServices.CharSet.Ansi)]
public struct ECWATCHDATA {
    
    /// WORD->unsigned short
    public ushort nState;
    
    /// WORD->unsigned short
    public ushort nIdx;
    
    /// WORD->unsigned short
    public ushort wDataCnt;
    
    /// char[20]
    [System.Runtime.InteropServices.MarshalAsAttribute(System.Runtime.InteropServices.UnmanagedType.ByValTStr, SizeConst=20)]
    public string szTime;
    
    /// char*
    public System.IntPtr lpIDString;
    
    /// char*
    public System.IntPtr lpNameString;
    
    /// char*[8]
    [System.Runtime.InteropServices.MarshalAsAttribute(System.Runtime.InteropServices.UnmanagedType.ByValArray, SizeConst=8, ArraySubType=System.Runtime.InteropServices.UnmanagedType.SysUInt)]
    public System.IntPtr[] lpData;
}