DataType转换为SqlDbType

      private SqlDbType GetDBType(System.Type theType)
        {
            SqlParameter p1;
            System.ComponentModel.TypeConverter tc;
            p1 = new SqlParameter();
            tc = System.ComponentModel.TypeDescriptor.GetConverter(p1.DbType);
            if (tc.CanConvertFrom(theType))
            {
                p1.DbType = tc.ConvertFrom(theType.Name);
            }
            else
            {        //Try brute force   
                try {
                    p1.DbType = tc.ConvertFrom(theType.Name);
                }
                catch (Exception ex)
                {                //Do Nothing   
                }
            }
            return p1.SqlDbType;
        }