请教一个问题

Question

        /// <summary>
        /// 结构体定义
        /// </summary>
        [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode, Pack = 4)]
        public class JSSJ_PlateIDConfig 
        {
            /// <summary>
            /// aaa
            /// </summary>
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 36)]
            public string aaa;            /// <summary>
            /// bbb
            /// </summary>
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 9)]
            public string bbb;
        }        public delegate int jskSDK(IntPtr pPlateConfig);//调用
jskSDK(pPlateConfig);
JSSJ_PlateIDConfig jssj = (JSSJ_PlateIDConfig)Marshal.PtrToStructure(pPlateConfig, typeof(JSSJ_PlateIDConfig));