把修改方法写活

 /// <summary>
        /// 修改一列数据
        /// </summary>
        public void UpdateField(string strWhere, string strValue)
        {
            StringBuilder strSql = new StringBuilder();
            strSql.Append("update 表名set " + strValue);
            strSql.Append(" where " + strWhere);
            执行sql.......
        }