C#调用C++dll,返回值为结构体,结构体值转换不对
C++dll的方法为 LPECWATCHDATA WINAPI ecwGetExternsionData(WORD widx);
LPECWATCHDATA是这样定义的
typedef struct {
WORD nState; //状态
WORD nIdx; //索引
WORD wDataCnt; //数据(lpData)项数
char szTime[20]; //时间
unsigned char* lpIDString; //设备号码
unsigned char* lpNameString; //设备/用户名称
LPCTSTR lpData[8];
}ECWATCHDATA,*LPECWATCHDATA;
我在C#里是这样转的 ECWATCHDATAeds = (ECWATCHDATA)(Marshal.PtrToStructure(ecwGetExternsionData(i), typeof(ExteECWATCHDATA))); ExternsionDataStruct是我自己定义的一个结构体,结构体为
[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 IntPtr lpIDString;
/// char*
public 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;
}
ECWATCHDATAeds = (ECWATCHDATA)(Marshal.PtrToStructure(ecwGetExternsionData(i), typeof(ECWATCHDATA))); 转化C#的结构体后里面有的值不对。像lpIDString,lpNameString和实际值对不上,这是什么原因?