帮楼主百度了一下
解决方法:
添加属性:CallingConvention=CallingConvention.Cdecl
如:
[DllImport("TwiHikVision.dll", EntryPoint="GetFirstPic",CallingConvention=CallingConvention.Cdecl)]
public static extern string GetFirstPic(string videoFileName, string exportFilePath);
http://blog.csdn.net/wjeson/article/details/8263320