NPOI Excel导入 导出

添加引用

using NPOI.HSSF.UserModel;
using NPOI.SS.UserModel;
using System;
using System.Collections.Generic;
using System.Data;
using System.IO;
using System.Text;

导入

  public DataSet ExcelToDataTable(string path)
         {
             DataSet dataSet1 = new DataSet();
             HSSFWorkbook hssfworkbook;
             using (FileStream file = new FileStream(path, FileMode.Open, FileAccess.Read))
             {
                 hssfworkbook = new HSSFWorkbook(file); //把xls文件中的数据写入hssfworkbook中

                 //for (int i = 0; i < hssfworkbook.NumberOfSheets; i++)  //NumberOfSheets是myxls.xls中总共的表数
                 //{
                 ISheet sheet = hssfworkbook.GetSheetAt();   //读取当前表数据

                 DataTable dt = new DataTable();

                 for (int j = ; j <= sheet.LastRowNum; j++)  //LastRowNum 是当前表的总行数
                 {
                     IRow row = sheet.GetRow(j);  //读取当前行数据
                     DataRow dr = dt.NewRow();
                     if (row != null)
                     {
                         //sbr.Append("-------------------------------------\r\n"); //读取行与行之间的提示界限
                         for (int k = ; k < row.LastCellNum; k++)  //LastCellNum 是当前行的总列数
                         {
                             ICell cell = row.GetCell(k);  //当前表格
                             if (cell != null)
                             {
                                 if (j == )
                                 {
                                     dt.Columns.Add(cell.ToString());
                                 }
                                 else
                                 {
                                     RegexHelper regexHelper = new RegexHelper();

                                     if (regexHelper.IsMatch(cell.ToString(), "[0-9]{1,2}/[0-9]{1,2}/[0-9]{2,4}"))
                                     {
                                         dr[k] = cell.DateCellValue.ToString();
                                     }
                                     else
                                     {
                                         dr[k] = cell.ToString();
                                     }
                                     //日期格式判断输出

                                 }
                                 //sbr.Append(cell.ToString());   //获取表格中的数据并转换为字符串类型

                             }
                         }//for
                     }// if (row != null)
                     if (j != )
                     {
                         dt.Rows.Add(dr);
                     }
                 }//for j

                 dataSet1.Tables.Add(dt);

                 //}

             }//using
             return dataSet1;
         }

导出

 #region "数据导出"
         /// <summary>
         /// WinForm DataTable数据导出Excel到本地
         /// </summary>
         /// <param name="table"></param>
         /// <param name="fileName"></param>
         public static void SaveToFile(DataTable table, string fileName)
         {
             using (FileStream fs = new FileStream(fileName, FileMode.Create, FileAccess.Write))
             {
                 MemoryStream ms = RenderToExcel(table);

                 byte[] data = ms.ToArray();

                 fs.Write(data, , data.Length);
                 fs.Flush();

                 data = null;
             }
         }
         public static MemoryStream RenderToExcel(DataTable table)
         {
             MemoryStream ms = new MemoryStream();

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

                         // 处理标题.
                         foreach (DataColumn column in table.Columns)
                             headerRow.CreateCell(column.Ordinal).SetCellValue(column.Caption);//如果标题没有设置,返回ColumnName的值

                         int rowIndex = ;

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

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

                             rowIndex++;
                         }

                         workbook.Write(ms);
                         ms.Flush();
                         ms.Position = ;
                     }
                 }
             }
             return ms;
         }

         /// <summary>
         /// Web DataTable 数据导出到浏览器客户端
         /// </summary>
         /// <param name="table"></param>
         /// <param name="context"></param>
         /// <param name="fileName"></param>
         static void RenderToBrowser(DataTable table, HttpContext context, string fileName)
         {
             MemoryStream ms = RenderToExcel(table);
             if (context.Request.Browser.Browser == "IE")
                 fileName = HttpUtility.UrlEncode(fileName);
             context.Response.AddHeader("Content-Disposition", "attachment;fileName=" + fileName);
             context.Response.BinaryWrite(ms.ToArray());
         }

         #endregion

调用  ExcelHelp类就是上面写的自定义类

  ExcelHelp ExcelHelp = new ExcelHelp();
             //导入Excel到datagridview
             dataGridView1.DataSource = ExcelHelp.ExcelToDataTable(txtfileurl.Text).Tables[];
             //导出
             saveFileDialog1.Filter = "Excel|*.Xls;";
             saveFileDialog1.FileName = "测试.Xls";
             if (saveFileDialog1.ShowDialog() == DialogResult.OK)
             {
                 ExcelHelp.SaveToFile(rptDst.Tables["interaction"], saveFileDialog1.FileName);
             }