使用NPOI导入导出Excel(xls/xlsx)数据到DataTable中

using System;

using System.Collections.Generic;

using System.Text;

using System.IO;

using NPOI.SS.UserModel;        //NPOI

using NPOI.HSSF.Util;           //NPOI

using NPOI.HSSF.UserModel;      //NPOI

using NPOI.XSSF.UserModel;      //NPOI

using System.Data.SqlClient;

using System.Data;

 请先下载NPOI的所有dll,然后Add reference.

1.导入

/// <summary>

/// Excel某sheet中内容导入到DataTable中

/// 区分xsl和xslx分别处理

/// </summary>

/// <param name="filePath">Excel文件路径,含文件全名</param>

/// <param name="sheetName">此Excel中sheet名</param>

/// <returns></returns>

public DataTable ExcelSheetImportToDataTable(string filePath, string sheetName)

{

            

    DataTable dt = new DataTable();



    if (Path.GetExtension(filePath).ToLower() == ".xls".ToLower())

    {//.xls

        #region .xls文件处理:HSSFWorkbook

        try

        {

            using (FileStream file = new FileStream(filePath, FileMode.Open, FileAccess.Read))

            {



                hssfworkbook = new HSSFWorkbook(file);

            }

        }

        catch (Exception e)

        {

            throw e;

        }            



        ISheet sheet = hssfworkbook.GetSheet(sheetName);

        System.Collections.IEnumerator rows = sheet.GetRowEnumerator();

        HSSFRow headerRow = (HSSFRow)sheet.GetRow(0);                



        //一行最后一个方格的编号 即总的列数  

        for (int j = 0; j < (sheet.GetRow(0).LastCellNum); j++)

        {

            //SET EVERY COLUMN NAME

            HSSFCell cell = (HSSFCell)headerRow.GetCell(j);



            dt.Columns.Add(cell.ToString());

        }



        while (rows.MoveNext())

        {

            IRow row = (HSSFRow)rows.Current;

            DataRow dr = dt.NewRow();



            if (row.RowNum == 0) continue;//The firt row is title,no need import



            for (int i = 0; i < row.LastCellNum; i++)

            {

                if (i>=dt.Columns.Count)//cell count>column count,then break //每条记录的单元格数量不能大于表格栏位数量 20140213

                {

                    break;

                }



                ICell cell = row.GetCell(i);



                if ((i==0)&&(string.IsNullOrEmpty(cell.ToString())==true))//每行第一个cell为空,break

                {

                    break;

                }



                if (cell == null)

                {

                    dr[i] = null;

                }

                else

                {

                    dr[i] = cell.ToString();

                }

            }

                    

            dt.Rows.Add(dr);

        }

        #endregion

    }

    else

    {//.xlsx

        #region .xlsx文件处理:XSSFWorkbook

        try

        {

            using (FileStream file = new FileStream(filePath, FileMode.Open, FileAccess.Read))

            {



                hssfworkbook = new XSSFWorkbook(file);

            }

        }

        catch (Exception e)

        {

            throw e;

        }            



        ISheet sheet = hssfworkbook.GetSheet(sheetName);

        System.Collections.IEnumerator rows = sheet.GetRowEnumerator();

        XSSFRow headerRow = (XSSFRow)sheet.GetRow(0);



                



        //一行最后一个方格的编号 即总的列数  

        for (int j = 0; j < (sheet.GetRow(0).LastCellNum); j++)

        {

            //SET EVERY COLUMN NAME

            XSSFCell cell = (XSSFCell)headerRow.GetCell(j);



            dt.Columns.Add(cell.ToString());



        }



        while (rows.MoveNext())

        {

            IRow row = (XSSFRow)rows.Current;

            DataRow dr = dt.NewRow();



            if (row.RowNum == 0) continue;//The firt row is title,no need import



            for (int i = 0; i < row.LastCellNum; i++)

            {

                if (i >= dt.Columns.Count)//cell count>column count,then break //每条记录的单元格数量不能大于表格栏位数量 20140213

                {

                    break;

                }



                ICell cell = row.GetCell(i);



                if ((i == 0) && (string.IsNullOrEmpty(cell.ToString()) == true))//每行第一个cell为空,break

                {

                    break;

                }



                if (cell == null)

                {

                    dr[i] = null;

                }

                else

                {

                    dr[i] = cell.ToString();

                }

            }

            dt.Rows.Add(dr);

        }

        #endregion

    }

    return dt;

}

 2.导出

 /// <summary>

        /// NPOI导出Excel，不依赖本地是否装有Excel，导出速度快

        /// </summary>

        /// <param name="dataGridView1">要导出的dataGridView控件</param>

        /// <param name="sheetName">sheet表名</param>

        /// 

        public static void ExportToExcel(DataGridView dataGridView1, string sheetName)

        {

            SaveFileDialog fileDialog = new SaveFileDialog();

            fileDialog.Filter = "Excel(97-2003)|*.xls";

            if (fileDialog.ShowDialog() == System.Windows.Forms.DialogResult.Cancel)

            {

                return;

            }

            //不允许dataGridView显示添加行，负责导出时会报最后一行未实例化错误

            dataGridView1.AllowUserToAddRows = false;

            HSSFWorkbook workbook = new HSSFWorkbook();

            ISheet sheet = workbook.CreateSheet(sheetName);

            IRow rowHead = sheet.CreateRow(0);



            //填写表头

            for (int i = 0; i < dataGridView1.Columns.Count; i++)

            {

                rowHead.CreateCell(i, CellType.String).SetCellValue(dataGridView1.Columns[i].HeaderText.ToString());

            }

            //填写内容

            for (int i = 0; i < dataGridView1.Rows.Count; i++)

            {

                IRow row = sheet.CreateRow(i + 1);

                for (int j = 0; j < dataGridView1.Columns.Count; j++)

                {

                    row.CreateCell(j, CellType.String).SetCellValue(dataGridView1.Rows[i].Cells[j].Value.ToString());

                }

            }



            using (FileStream stream = File.OpenWrite(fileDialog.FileName))

            {

                workbook.Write(stream);

                stream.Close();

            }

            MessageBox.Show("导出数据成功!", "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);

            GC.Collect();

        }