不吃饭,裸体等答案
c++原型:

typedef struct {
BYTE sSerialNumber[12]; //序列号
BYTE byAlarmInPortNum;//DVR报警输入个数
BYTE byAlarmOutPortNum;//DVR报警输出个数
BYTE byDiskNum;//DVR 硬盘个数
BYTE byDVRType;//DVR类型,
BYTE byChanNum;//DVR 通道个数
BYTE byStartChan;//起始通道号,例如DVS-1,DVR - 1
}NET_DVR_DEVICEINFO, *LPNET_DVR_DEVICEINFO;

LONG __stdcall NET_DVR_Login(char *sDVRIP,WORD wDVRPort,
char *sUserName,char *sPassword,LPNET_DVR_DEVICEINFO lpDeviceInfo);
c++代码测试正确

用c#转换代码如下:

public struct NET_DVR_DEVICEINFO
{
public byte[] sSerialNumber;
public byte byAlarmInPortNum;
public byte byAlarmOutPortNum;
public byte byDiskNum;
public byte byDVRType;
public byte byChanNum;
public byte byStartChan;

}
c#调用:
[DllImport( "HCNetSDK.dll ", EntryPoint = "NET_DVR_Login ", CallingConvention = CallingConvention.StdCall)]
private static extern Int32 NET_DVR_Login(string sDVRIP, Int16 wDVRPort, string sUserName, string sPassword, ref NET_DVR_DEVICEINFO lpDeviceInfo);

出现 "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。 "错误
请教高手们,哪里出错了呢


[解决办法]
public struct NET_DVR_DEVICEINFO
{
［MarshalAs(UnManageType.ByValArray,SizeConst=12)]//要加上这句！
public byte[] sSerialNumber;
public byte byAlarmInPortNum;
public byte byAlarmOutPortNum;
public byte byDiskNum;
public byte byDVRType;
public byte byChanNum;
public byte byStartChan;

}
[解决办法]
获取硬件信息源代码（包括CPU,内存，硬盘信息）:
http://www.msproject.cn/Article/GetHardwareInformation.aspx

希望有帮助