EXCEL读写NPOI--导出功能

第一步：将NPOI中的一下三个文件复制到项目中

第二部在项目中为其添加引用，在右击引用，在浏览选项卡上。

在导出的按钮上添加CLlck事件。代码如下：

 

 private void btnExportToExcel_Click(object sender, RoutedEventArgs e)
        {

            SaveFileDialog sdfExport = new SaveFileDialog();
            sdfExport.Filter = "Excel文件|*.xls";
            if (sdfExport.ShowDialog() != true)
            {
                return;
            }

            string filename = sdfExport.FileName;
            HSSFWorkbook workbook = new HSSFWorkbook();
            ISheet sheet = workbook.CreateSheet("员工数据");

            IRow rowHeader = sheet.CreateRow(0);//表头行
            rowHeader.CreateCell(0, CellType.STRING).SetCellValue("姓名");
            rowHeader.CreateCell(1, CellType.STRING).SetCellValue("工号");
            rowHeader.CreateCell(2, CellType.STRING).SetCellValue("入职日期");

            //把查询结果导出到Excel
            Employee[] employees = (Employee[])datagrid.ItemsSource;
            for (int i = 0; i < employees.Length; i++)
            {
                Employee employee = employees[i];
                IRow row = sheet.CreateRow(i + 1);
                row.CreateCell(0, CellType.STRING).SetCellValue(employee.Name);
                row.CreateCell(1, CellType.STRING).SetCellValue(employee.Number);

                ICellStyle styledate = workbook.CreateCellStyle();
                IDataFormat format = workbook.CreateDataFormat();
                //格式具体有哪些请看单元格右键中的格式，有说明
                styledate.DataFormat = format.GetFormat("yyyy\"年\"m\"月\"d\"日\"");

                ICell cellInDate = row.CreateCell(2, CellType.NUMERIC);
                cellInDate.CellStyle = styledate;
                cellInDate.SetCellValue(employee.InDate);
            }

            using (Stream stream = File.OpenWrite(filename))
            {
                workbook.Write(stream);
            }
        }