c#调用c++ api函数之参数类型问题

c++函数定义如下
extern "C"
{

struct  colorstruct
{
double dbValueInterval;
CString  str;
IColorPtr ipColor;
colorstruct()
{
str = _T(" ");
dbValueInterval = 0.0;
ipColor.CreateInstance(CLSID_RgbColor);
}


};

__declspec(dllexport) void CressmantestforSK (int a,int irad,float * rads,int isiz,int jsiz,float dbCellSize,double lnmin,double lnmax,double ltmin,double ltmax,long stnnum,float *stnlon,float *stnlat,float *stnrpt,float *grid,colorstruct *colorArray,int iLineNum,float NoDefineVale);


}

C#中extern 如下
        [DllImport("CressmanforSk24.dll")]
        public extern static void CressmantestforSK( //__declspec(dllexport) void CressmantestforSK (
            int a,                     //    int a,
            int irad,                  //    int irad,
            Single[] rads,              //    Single * rads,
            int isiz,                  //    int isiz,
            int jsiz,                  //    int jsiz,
            Single dbCellSize,          //    Single dbCellSize,
            double lnmin,              //    double lnmin,
            double lnmax,              //    double lnmax,
            double ltmin,              //    double ltmin,
            double ltmax,              //    double ltmax,
            long stnnum,               //    long stnnum,
            Single[] stnlon,            //    Single *stnlon,
            Single[] stnlat,            //    Single *stnlat,
            Single[] stnrpt,            //    Single *stnrpt,
            out Single[] grid,          //    Single *grid,
            colorstruct[] colorArray,  //    colorstruct *colorArray,
            int iLineNum,              //    int iLineNum,
            Single NoDefineVale         //    Single NoDefineVale
            );                         //    );


    public struct colorstruct
    {
        /// <summary>
        /// 数值
        /// </summary>
        [MarshalAs(UnmanagedType.R8)]
        public double dbValueInterval;// = 0;
        /// <summary>
        /// 名称
        /// </summary>
        [MarshalAs(UnmanagedType.LPStr)]
        public string str;// = " "
        /// <summary>
        /// 颜色
        /// </summary>
        [MarshalAs(UnmanagedType.Interface)]
        public IColor ipColor;// = new RgbColorClass()


        //void colorstruct()
        //{
        //    str = _T(" ");
        //    dbValueInterval = 0.0;
        //    ipColor.CreateInstance(CLSID_RgbColor);
        //}
    };

报错 ：尝试读取或写入受保护的内存，内存已损坏


初步确定是参数类型对应的问题，谁能帮帮我啊 
msn:jpu_jacky@eyou.com