修改数据表DataTable某一列的类型和记录值(正确步骤：1.克隆表结构，2.修改列类型，3.修改记录值，4.返回希望的结果)

    /// <summary>
    /// 修改数据表DataTable某一列的类型和记录值(正确步骤：1.克隆表结构，2.修改列类型，3.修改记录值，4.返回希望的结果)
    /// </summary>
    /// <param name="argDataTable">数据表DataTable</param>
    /// <returns>数据表DataTable</returns>
    private DataTable UpdateDataTable(DataTable argDataTable)
    {
        DataTable dtResult = new DataTable();
        //克隆表结构
        dtResult = argDataTable.Clone();
        foreach (DataColumn col in dtResult.Columns)
        {
            if (col.ColumnName == "age")
            {
                //修改列类型
                col.DataType = typeof(String);
            }
        }
        foreach (DataRow row in argDataTable.Rows)
        {
            DataRow rowNew = dtResult.NewRow();
            rowNew["MemberId"] = row["MemberId"];
            rowNew["NickName"] = row["NickName"];
            //修改记录值
            rowNew["age"] = row["age"] + "岁";
            dtResult.Rows.Add(rowNew);
        }
        //返回希望的结果
        return dtResult;
    }