/// <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 == "RQ")

                {

                    //修改列类型

                    col.DataType = typeof(String);

                }

            }

            foreach (DataRow row in argDataTable.Rows)

            {

                DataRow rowNew = dtResult.NewRow();

                rowNew["DTBM"] = row["DTBM"];

                //修改记录值

                rowNew["RQ"] = Convert.ToDateTime(row["RQ"]).ToString("yyyy-MM-dd").ToString();

                rowNew["DWBM"] = row["DWBM"];

                rowNew["DWMC"] = row["DWMC"];

                rowNew["YYID"] = row["YYID"];

                rowNew["YYMC"] = row["YYMC"];

                rowNew["YXCL"] = row["YXCL"];

                dtResult.Rows.Add(rowNew);

            }

            return dtResult;

        }