NPOI操作

1.操作Excel

　　准备生成的公共方法(将数据源DataTable转换成MemoryStream)

         /// <summary>
         /// 生成Excel
         /// </summary>
         /// <param name="table">DataTable</param>
         /// <returns>MemoryStream</returns>
         public static MemoryStream BuildToExcel(DataTable table)
         {
             MemoryStream ms = new MemoryStream();

             using (table)
             {
                 using (IWorkbook workbook = new HSSFWorkbook())
                 {
                     using (ISheet sheet = workbook.CreateSheet())
                     {
                         IRow headerRow = sheet.CreateRow();

                         // handling header.
                         foreach (DataColumn column in table.Columns)
                         {
                             headerRow.CreateCell(column.Ordinal).SetCellValue(column.Caption);
                         }

                         // handling value.
                         int rowIndex = ;

                         foreach (DataRow row in table.Rows)
                         {
                             IRow dataRow = sheet.CreateRow(rowIndex);

                             foreach (DataColumn column in table.Columns)
                             {
                                 dataRow.CreateCell(column.Ordinal, CellType.STRING).SetCellValue(row[column].ToString());
                             }

                             rowIndex++;
                         }

                         AutoSizeColumns(sheet);
                         workbook.Write(ms);
                         ms.Flush();
                         ms.Position = ;
                     }
                 }
             }

             return ms;
         }

MVC导出

         /// <summary>
         /// 下载excel文件
         /// </summary>
         /// <param name="fileName">文件名称</param>
         /// <param name="dataTable">数据源</param>
         /// <returns>FileResult</returns>
         private FileResult DownloadExcel(string fileName, DataTable dataTable)
         {
             MemoryStream stream = WalletComm.BuildToExcel(dataTable);
             stream.Seek(, SeekOrigin.Begin);
             return File(stream, "application/vnd.ms-excel", fileName);
         }

2.操作CSV

　　准备生成的公共方法(将数据源DataTable转换成MemoryStream)

         /// <summary>
         /// 生成CSV
         /// </summary>
         /// <param name="table">DataTable</param>
         /// <returns>MemoryStream</returns>
         public static MemoryStream BuildToCsv(DataTable table)
         {
             Encoding encode = Encoding.GetEncoding("gb2312");
             StringBuilder str = new StringBuilder();
             if (table != null && table.Columns.Count >  && table.Rows.Count > )
             {
                 for (int i = ; i < table.Columns.Count; i++)
                 {
                     str.Append(table.Columns[i].ColumnName.Replace("\"", "\"\""));
                     if (i < table.Columns.Count - )
                     {
                         str.Append(",");
                     }
                 }

                 foreach (DataRow item in table.Rows)
                 {
                     str.Append("\r\n");
                     for (int i = ; i < table.Columns.Count; i++)
                     {
                         if (item[i] != null)
                         {
                             str.Append("'").Append(item[i].ToString().Replace("\"", "\"\""));
                         }

                         if (i < table.Columns.Count - )
                         {
                             str.Append(",");
                         }
                     }
                 }
             }

             MemoryStream stream = new MemoryStream(encode.GetBytes(str.ToString()));
             return stream;
         }

　　MVC导出

         /// <summary>
         /// 下载csv文件
         /// </summary>
         /// <param name="fileName">文件名称</param>
         /// <param name="dataTable">数据源</param>
         /// <returns>FileResult</returns>
         private FileResult DownloadCsv(string fileName, DataTable dataTable)
         {
             MemoryStream stream = WalletComm.BuildToCsv(dataTable);
             stream.Seek(, SeekOrigin.Begin);
             return File(stream, "text/comma-separated-values", fileName);
         }

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