用NPOI从DataBase到Excel

NPOI的C# Helper代码

         public static void WriteExcel(DataTable dt, string filePath)
         {
             if (!string.IsNullOrEmpty(filePath) && dt.Rows.Count > )
             {
                 HSSFWorkbook wk = new HSSFWorkbook();
                 ISheet sheet = wk.CreateSheet(dt.TableName);

                 //列头
                 IRow headerRow = sheet.CreateRow();
                 for (int i = ; i < dt.Columns.Count; i++)
                 {
                     headerRow.CreateCell(i).SetCellValue(dt.Columns[i].ColumnName);
                 }

                 //填充内容
                 for (int i = ; i < dt.Rows.Count; i++) //注意条件dt.Rows.Count
                 {
                     IRow row = sheet.CreateRow(i+);
                     for (int j = ; j < dt.Columns.Count; j++)//注意条件dt.Columns.Count
                     {
                         row.CreateCell(j).SetCellValue(Convert.ToString(dt.Rows[i][j])); //注意这里写法
                     }
                 }
                 //写入到客户端
                 using (MemoryStream ms = new MemoryStream())
                 {
                     wk.Write(ms);
                     using (FileStream file = new FileStream(filePath, FileMode.Create, FileAccess.Write))
                     {
                         byte[] data = ms.ToArray();
                         file.Write(data,,data.Length);
                         file.Flush();
                     }
                     wk = null;
                 }

             }
         }