为什么循环提取的结果是同样的字符？？？

m为Match的对象，我的这个循环得到的字符为什么全是一样的？？？高手指点

                for(m=RStr.Match(Str.ToString());m.Success;m.NextMatch())
                {
                    i++;//i为子分类ID
                    T1=m.Groups["port"].Index;
                    Str.Remove(0,T1);
                    m.Result("${proto}${port}");
                    url=m.Groups["proto"].ToString();
                    Type1=m.Groups["port"].ToString();

                    dataHelper DataB=new dataHelper();
                    SqlCommand cmd=DataB.Sqlcmd("Up_productPratclassAdd",CommandType.StoredProcedure);
                    DataB.Parameters(j.ToString(),"@Mid",cmd);
                    DataB.Parameters(i.ToString(),"@Pid",cmd);
                    DataB.Parameters(Type1,"@Type1",SqlDbType.NVarChar,40,cmd);
                    DataB.Parameters(Type1,"@Mem",cmd);
                    DataB.SqlOpen();
                    cmd.ExecuteNonQuery();
                    DataB.SqlClose();
                }