Excel导入导出

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using NPOI;
using NPOI.HPSF;
using NPOI.HSSF;
using NPOI.HSSF.UserModel;
using NPOI.POIFS;
using NPOI.Util;
using System.IO;
using System.Data;

namespace npoivideo  {
    public class DataTableRenderToExcel
    {
        public static Stream RenderDataTableToExcel(DataTable SourceTable)
        {
            HSSFWorkbook workbook = new HSSFWorkbook();
            MemoryStream ms = new MemoryStream();
            HSSFSheet sheet = (HSSFSheet)workbook.CreateSheet();
            HSSFRow headerRow = (HSSFRow)sheet.CreateRow(0);

            // handling header.
            foreach (DataColumn column in SourceTable.Columns)
                headerRow.CreateCell(column.Ordinal).SetCellValue(column.ColumnName);

            // handling value.
            int rowIndex = 1;

            foreach (DataRow row in SourceTable.Rows)
            {
                HSSFRow dataRow = (HSSFRow)sheet.CreateRow(rowIndex);

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

                rowIndex++;
            }

            workbook.Write(ms);
            ms.Flush();
            ms.Position = 0;

            sheet = null;
            headerRow = null;
            workbook = null;

            return ms;
        }

        public static void RenderDataTableToExcel(DataTable SourceTable, string FileName)
        {
            MemoryStream ms = RenderDataTableToExcel(SourceTable) as MemoryStream;
            FileStream fs = new FileStream(FileName, FileMode.Create, FileAccess.Write);
            byte[] data = ms.ToArray();

            fs.Write(data, 0, data.Length);
            fs.Flush();
            fs.Close();

            data = null;
            ms = null;
            fs = null;
        }

        public static DataTable RenderDataTableFromExcel(Stream ExcelFileStream, string SheetName, int HeaderRowIndex)
        {
            HSSFWorkbook workbook = new HSSFWorkbook(ExcelFileStream);
            HSSFSheet sheet = (HSSFSheet)workbook.GetSheet(SheetName);

            DataTable table = new DataTable();

            HSSFRow headerRow = (HSSFRow)sheet.GetRow(HeaderRowIndex);
            int cellCount = headerRow.LastCellNum;

            for (int i = headerRow.FirstCellNum; i < cellCount; i++)
            {
                DataColumn column = new DataColumn(headerRow.GetCell(i).StringCellValue);
                table.Columns.Add(column);
            }

            int rowCount = sheet.LastRowNum;

            for (int i = (sheet.FirstRowNum + 1); i < sheet.LastRowNum; i++)
            {
                HSSFRow row = (HSSFRow)sheet.GetRow(i);
                DataRow dataRow = table.NewRow();

                for (int j = row.FirstCellNum; j < cellCount; j++)
                    dataRow[j] = row.GetCell(j).ToString();
            }

            ExcelFileStream.Close();
            workbook = null;
            sheet = null;
            return table;
        }

        public static DataTable RenderDataTableFromExcel(Stream ExcelFileStream, int SheetIndex, int HeaderRowIndex)
        {
            HSSFWorkbook workbook = new HSSFWorkbook(ExcelFileStream);
            HSSFSheet sheet = (HSSFSheet)workbook.GetSheetAt(SheetIndex);

            DataTable table = new DataTable();

            HSSFRow headerRow = (HSSFRow)sheet.GetRow(HeaderRowIndex);
            int cellCount = headerRow.LastCellNum;

            for (int i = headerRow.FirstCellNum; i < cellCount; i++)
            {
                DataColumn column = new DataColumn(headerRow.GetCell(i).StringCellValue);
                table.Columns.Add(column);
            }

            int rowCount = sheet.LastRowNum;

            for (int i = (sheet.FirstRowNum + 1); i < sheet.LastRowNum; i++)
            {
                HSSFRow row = (HSSFRow)sheet.GetRow(i);
                DataRow dataRow = table.NewRow();

                for (int j = row.FirstCellNum; j < cellCount; j++)
                {
                    if (row.GetCell(j) != null)
                        dataRow[j] = row.GetCell(j).ToString();
                }

                table.Rows.Add(dataRow);
            }

            ExcelFileStream.Close();
            workbook = null;
            sheet = null;
            return table;
        }

        /// <summary>读取excel
        /// 默认第一行为标头
        /// </summary>
        /// <param name="path">excel文档路径</param>
        /// <returns></returns>
        public static DataTable RenderDataTableFromExcel(string path)
        {
            DataTable dt = new DataTable();

            HSSFWorkbook hssfworkbook;
            using (FileStream file = new FileStream(path, FileMode.Open, FileAccess.Read))
            {
                hssfworkbook = new HSSFWorkbook(file);
            }
            HSSFSheet sheet = (HSSFSheet)hssfworkbook.GetSheetAt(0);
            System.Collections.IEnumerator rows = sheet.GetRowEnumerator();

            HSSFRow headerRow = (HSSFRow)sheet.GetRow(0);
            int cellCount = headerRow.LastCellNum;

            for (int j = 0; j < cellCount; j++)
            {
                HSSFCell cell = (HSSFCell)headerRow.GetCell(j);
                dt.Columns.Add(cell.ToString());
            }

            for (int i = (sheet.FirstRowNum + 1); i <= sheet.LastRowNum; i++)
            {
                HSSFRow row = (HSSFRow)sheet.GetRow(i);
                DataRow dataRow = dt.NewRow();

                for (int j = row.FirstCellNum; j < cellCount; j++)
                {
                    if (row.GetCell(j) != null)
                        dataRow[j] = row.GetCell(j).ToString();
                }

                dt.Rows.Add(dataRow);
            }
            return dt;
        }
    }
}

//查看所有学生列表
protected void ShowStu(object sender, EventArgs e)    //双击查看事件
{
AccessHelper helper = new AccessHelper();
helper.CreateCommand("select * from stu");
DataTable dt = helper.ExecuteQuery();
GridView1.DataSource = dt;
GridView1.DataBind();
}
//导出
protected void Output(object sender, EventArgs e)    //导出事件
{
AccessHelper helper = new AccessHelper();
helper.CreateCommand("select * from stu");
DataTable dt = helper.ExecuteQuery();
MemoryStream ms = DataTableRenderToExcel.RenderDataTableToExcel(dt) as MemoryStream;
Response.AddHeader("Content-Disposition", string.Format("attachment; filename=Download.xls"));
Response.BinaryWrite(ms.ToArray());
ms.Close();
ms.Dispose();
}
//导入
protected void Import(object sender, EventArgs e)    //导入事件
{
//上传xls文件到服务器上
if (!FileUpload1.HasFile)
{
Response.Write("请选择上传的文件.");
return;
}
if (!Directory.Exists(Server.MapPath("upload")))
{
Directory.CreateDirectory(Server.MapPath("upload"));
}
FileUpload1.SaveAs(Server.MapPath("upload/import.xls"));

DataTable dt = DataTableRenderToExcel.RenderDataTableFromExcel(MapPath("upload/import.xls"));
//GridView1.DataSource = dt;
//GridView1.DataBind();

int allcount = dt.Rows.Count; //总数
int incount = 0; //导入数
AccessHelper helper = new AccessHelper();
foreach (DataRow row in dt.Rows)
{
string name = row["姓名"].ToString();
string no = row["学号"].ToString();
string birthday = row["生日"].ToString();

if (ExistsNo(no))
{
continue;
}

string sql = "insert into stu(stuname,stuno,birthday) values(?,?,?)";
helper.CreateCommand(sql);
helper.AddParameter("?", name);
helper.AddParameter("?", no);
helper.AddParameter("?", birthday);
helper.ExecuteNonQuery();
incount++;
}
Response.Write("总数:" + allcount + ",导入成功:" + incount);
}