使用NPOI和委托做EXCEL导出

首先，在用NPOI导出时，学习了邀月这篇文章NPOI根据Excel模板生成原生的Excel文件实例，在这里先行谢过了。

本篇文章在邀月的基本上，做了一些小的改动，加上委托的机制。因为在做导出时，加载模板，下载为EXCEL的代码相同，但是在设置EXCEL模板中的值时有很大的不同。所以以了一些小的改动。

改动后的主要类文件如下：

ExcelHelper:

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public class ExcelHelper{private string templatePath;private string newFileName;private string templdateName;private string sheetName;public string SheetName{get { return sheetName; }set { sheetName = value; }}public ExcelHelper(string templdateName, string newFileName){this.sheetName = "sheet1";templatePath = HttpContext.Current.Server.MapPath("/") + "/Config/Template/";this.templdateName = string.Format("{0}{1}", templatePath, templdateName);this.newFileName = newFileName;}public void ExportDataToExcel(Action<HSSFSheet> actionMethod){using (MemoryStream ms = SetDataToExcel(actionMethod)){byte[] data = ms.ToArray();#region response to the clientHttpResponse response = System.Web.HttpContext.Current.Response;response.Clear();response.Charset = "UTF-8";response.ContentType = "application/vnd-excel";//"application/vnd.ms-excel";System.Web.HttpContext.Current.Response.AddHeader("Content-Disposition", string.Format("attachment; filename=" + newFileName));System.Web.HttpContext.Current.Response.BinaryWrite(data);#endregion}}private MemoryStream SetDataToExcel(Action<HSSFSheet> actionMethod){//Load template fileFileStream file = new FileStream(templdateName, FileMode.Open, FileAccess.Read);HSSFWorkbook workbook = new HSSFWorkbook(file);HSSFSheet sheet = workbook.GetSheet(SheetName);if (actionMethod != null) actionMethod(sheet);sheet.ForceFormulaRecalculation = true;using (MemoryStream ms = new MemoryStream()){workbook.Write(ms);ms.Flush();ms.Position = 0;sheet = null;workbook = null;return ms;}}}

PrintManager:

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public class PrintManager{public void PrintPurchase(){ExcelHelper helper = new ExcelHelper("PurchaseOrder.xls", "PurchaseOrder_C000001.xls");helper.ExportDataToExcel(SetPurchaseOrder);}private void SetPurchaseOrder(HSSFSheet sheet){HSSFRow row = null;HSSFCell cell = null;row = sheet.GetRow(2);cell = row.GetCell(1);cell.SetCellValue("C0000001");cell = row.GetCell(7);cell.SetCellValue("2013-04-18");DataTable itemDT = PrepareItemDTForTest();SetDataTableValue(sheet, 7, 0, itemDT);row = sheet.GetRow(14);cell = row.GetCell(0);cell.SetCellValue("NOKIA");cell = row.GetCell(6);cell.SetCellValue("CMCC");}public void SetDataTableValue(HSSFSheet sheet, int rowIndex, int columnIndex,DataTable dt) {HSSFRow row = null;HSSFCell cell = null;foreach (DataRow dataRow in dt.Rows){row = sheet.GetRow(rowIndex);columnIndex = 0;foreach (DataColumn column in dt.Columns){cell = row.GetCell(columnIndex);string drValue = dataRow[column].ToString();switch (column.DataType.ToString()){case "System.String":cell.SetCellValue(drValue);break;case "System.DateTime":DateTime dateV;DateTime.TryParse(drValue, out dateV);cell.SetCellValue(dateV);break;case "System.Boolean":bool boolV = false;bool.TryParse(drValue, out boolV);cell.SetCellValue(boolV);break;case "System.Int16":case "System.Int32":case "System.Int64":case "System.Byte":int intV = 0;int.TryParse(drValue, out intV);cell.SetCellValue(intV);break;case "System.Decimal":case "System.Double":double doubV = 0;double.TryParse(drValue, out doubV);cell.SetCellValue(doubV);break;case "System.DBNull":cell.SetCellValue("");break;default:cell.SetCellValue("");break;}columnIndex++;}rowIndex++;}}private DataTable PrepareItemDTForTest() {DataTable itemDT = new DataTable();itemDT.Columns.Add("Name");itemDT.Columns.Add("Qty", Type.GetType("System.Decimal"));itemDT.Columns.Add("UnitPrice", Type.GetType("System.Decimal"));DataRow newRow = itemDT.NewRow();newRow[0] = "820";newRow[1] = "100";newRow[2] = "3000";itemDT.Rows.Add(newRow);DataRow newRow2 = itemDT.NewRow();newRow2[0] = "920";newRow2[1] = "100";newRow2[2] = "4000";itemDT.Rows.Add(newRow2);return itemDT;}}