修改DataTable所有列的类型和记录值以便导出至Excel(2)

         该方法把DataTable中的非string类型的数据改为string类型，以避免导出到Excel表时显示错误。

        public DataTable changeDT(DataTable dt)
        {
            DataTable datatable = new DataTable();
            datatable = dt.Clone();
            foreach (DataColumn col in datatable.Columns)
            {
                if (col.DataType != typeof(string))
                {
                    col.DataType = typeof(string);
                }
            }
            foreach (DataRow row in dt.Rows)
            {
                DataRow nr = datatable.NewRow();
                for (int i = 0; i < dt.Columns.Count; i++)
                {
                    nr[i] = row[i].ToString();
                }
                datatable.Rows.Add(nr);
            }
            return datatable;
        }