C# MVC 自定义ActionResult实现EXCEL下载

前言

　　在WEB中，经常要使用到将数据转换成EXCEL，并进行下载。这里整理资料并封装了一个自定义ActionResult类，便于使用。如果文章对你有帮助，请点个赞。

　　话不多少，这里转换EXCEL使用的NPOI。还是用了一下反射的知识，便于识别实体类的一些自定义特性。

一、自定义一个Attribute

using System;namespace WebSeat.Entity.Member.Attributes
{/// <summary>/// 说明:Excel属性特性/// 创建日期：2016/12/13 14:24:13/// 创建人：曹永承/// </summary>[AttributeUsage(AttributeTargets.All, Inherited = false, AllowMultiple = true), Serializable]public class ExcelDataOptionAttribute:Attribute{/// <summary>/// 显示列下标/// </summary>public ushort ColumnIndex { get; set; }/// <summary>/// 显示名称/// </summary>public string DisplayName { get; set; }/// <summary>/// 列宽/// </summary>public int ColumnWidth { get; set; }/// <summary>/// 单元格数据格式/// </summary>public string Formater { get; set; }}}

该Attribute用于标记到实体对象的属性上，后面通过反射来识别具体的值

二、定义一个实体类

using WebSeat.Entity.Member.Attributes;namespace WebSeat.Entity.Member.Excel
{/// <summary>/// 说明:市首页数据统计Excel表格样式/// 创建日期：2016/12/13 14:19:27/// 创建人：曹永承/// </summary>public class CityStatics{[ExcelDataOption(ColumnIndex = 0, DisplayName = "时段",Formater ="@", ColumnWidth = 14)]public string DataDuring { get; set; }[ExcelDataOption(ColumnIndex =1,DisplayName ="城市",ColumnWidth =14)]public string City { get; set; }[ExcelDataOption(ColumnIndex = 2, DisplayName = "登录人数", ColumnWidth = 12)]public int StudentLoginedCount { get; set; }[ExcelDataOption(ColumnIndex = 3,DisplayName ="登录次数", ColumnWidth = 12)]public int StudentLoginTimes { get; set; }[ExcelDataOption(ColumnIndex = 4,DisplayName ="登录率",Formater ="0.00%", ColumnWidth = 12)]public decimal StudentLoginRatio { get; set; }[ExcelDataOption(ColumnIndex = 5,DisplayName ="学习节数", ColumnWidth = 12)]public int StudyPeriod { get; set; }[ExcelDataOption(ColumnIndex = 6, DisplayName = "学习次数", ColumnWidth = 12)]public int StudyTimes { get; set; }[ExcelDataOption(ColumnIndex = 7, DisplayName = "人均学习节数(节/人)", Formater = "0.00", ColumnWidth =23)]public decimal StudyRatio { get; set; }[ExcelDataOption(ColumnIndex = 8, DisplayName = "转化率",Formater = "0.00%", ColumnWidth = 12)]public decimal StudyConvertRatio { get; set; }}
}

注意：如果属性没有标注ExcelDataOption特性，那么该属性是不会导出到EXCEL中。

　　　ExcelDataOption中Formater属性，是设置单元格数据类型，这里对于excel中单元格的数据显示个数，例如上面"0.00%"表示以百分百的形式显示数字，且保留2位有效小数

三、定义一个Excel导出父类

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Web;
using System.Web.Mvc;
using WebSeat.Site.Member.Helper;namespace WebSeat.Site.Member.CustomResult
{/// <summary>/// 说明:导出Excel/// 创建日期：2016/12/13 13:12:37/// 创建人：曹永承/// </summary>public abstract class ExcelBaseResult<T> :ActionResult{#region 属性/// <summary>/// 数据实体/// </summary>public IList<T> Entity { get; set; }/// <summary>/// 下载文件名称(不包含扩展名)/// </summary>public string FileName { get; set; }/// <summary>/// 是否显示标题/// </summary>public bool ShowTitle { get; set; }/// <summary>/// 标题/// </summary>public string Title { get; set; }/// <summary>/// ContentType/// </summary>public string ContentType { get; set; }/// <summary>/// 扩展名/// </summary>public string ExtName { get; set; }/// <summary>/// 获取下载文件全名/// </summary>public string FullName { get { return FileName + ExtName; } }#endregion#region 构造函数public ExcelBaseResult(IList<T> entity, string fileName,bool showTitle,string title){this.Entity = entity;this.FileName = fileName;this.ShowTitle = showTitle;this.Title = title;}#endregion#region 抽象方法public abstract MemoryStream GetExcelStream();#endregion#region 重写ExecuteResultpublic override void ExecuteResult(ControllerContext context){using(MemoryStream ms = GetExcelStream()){context.HttpContext.Response.AddHeader("Content-Length", ms.Length.ToString());context.HttpContext.Response.ContentType = ContentType;context.HttpContext.Response.AddHeader("Content-Disposition", "attachment; filename=" + FullName.EncodingDownloadFileName());ms.Seek(0, SeekOrigin.Begin);Stream output = context.HttpContext.Response.OutputStream;byte[] bytes = new byte[1024 * 10];int readSize = 0;while ((readSize = ms.Read(bytes, 0, bytes.Length)) > 0){output.Write(bytes, 0, readSize);context.HttpContext.Response.Flush();}}}#endregion}
}

主要因为Excel有不同版本，所有定义了一个父类，其子类只需要实现方法

public abstract MemoryStream GetExcelStream();

四、定义一个子类继承ExcelBaseResult

　　这里实现了一个导出.xls格式（2003版本的）到子类

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Web;
using System.Web.Mvc;
using NPOI.HSSF.UserModel;
using NPOI.SS.UserModel;
using WebSeat.Entity.Member.Attributes;
using WebSeat.Site.Member.CustomResult;namespace WebSeat.Site.Member.CustomResult
{/// <summary>/// 说明:导出成.xls格式的Excel/// 创建日期：2016/12/13 13:51:23/// 创建人：曹永承/// </summary>public class Excel2003Result<T>: ExcelBaseResult<T> where T:new(){public Excel2003Result(IList<T> entity, string fileName,bool showTitle,string title):base(entity,  fileName,  showTitle,  title){ContentType = "application/vnd.ms-excel";ExtName = ".xls";}public override MemoryStream GetExcelStream(){MemoryStream ms = new MemoryStream();//获取实体属性PropertyInfo[] propertys = typeof(T).GetProperties();if (propertys.Count() == 0){return ms;}//创建Excel对象IWorkbook book = new HSSFWorkbook();//添加一个sheetISheet sheet1 = book.CreateSheet("Sheet1");var index = ShowTitle ? 1 : 0;//样式设置IFont cellfont = book.CreateFont();cellfont.FontHeightInPoints = 11;cellfont.FontName = "宋体";ICellStyle cellStyle = book.CreateCellStyle();cellStyle.VerticalAlignment = VerticalAlignment.Center;cellStyle.Alignment = HorizontalAlignment.Center;cellStyle.SetFont(cellfont);IRow rowColumnHead = sheet1.CreateRow(index);IDataFormat format = book.CreateDataFormat();ushort firstColumn = ushort.MaxValue, lastColumn = ushort.MinValue;  //第一列下标和最后一列下标//添加列头for (int j = 0; j < propertys.Count(); j++){ExcelDataOptionAttribute dataOption = propertys[j].GetCustomAttribute<ExcelDataOptionAttribute>();if (dataOption == null){continue;}IFont font = book.CreateFont();font.FontHeightInPoints = 11;font.FontName = "宋体";ICellStyle style = book.CreateCellStyle();style.VerticalAlignment = VerticalAlignment.Center;style.Alignment = HorizontalAlignment.Center;style.SetFont(font);if (!string.IsNullOrWhiteSpace(dataOption.Formater)){style.DataFormat = format.GetFormat(dataOption.Formater);}sheet1.SetDefaultColumnStyle(dataOption.ColumnIndex, style);ICell cell = rowColumnHead.CreateCell(dataOption.ColumnIndex);cell.SetCellValue(dataOption.DisplayName);firstColumn = firstColumn < dataOption.ColumnIndex ? firstColumn : dataOption.ColumnIndex;lastColumn = lastColumn > dataOption.ColumnIndex ? lastColumn : dataOption.ColumnIndex;}index = ShowTitle ? 2 : 1;//将各行数据显示出来for (int i = 0; i < Entity.Count; i++){IRow row = sheet1.CreateRow(i + index);//循环各属性，添加列for (int j = 0; j < propertys.Count(); j++){ExcelDataOptionAttribute dataOption = propertys[j].GetCustomAttribute<ExcelDataOptionAttribute>();if (dataOption == null){continue;}ICell cell = row.CreateCell(dataOption.ColumnIndex);//样式设置//cell.CellStyle = cellStyle;if (dataOption.ColumnWidth != 0){sheet1.SetColumnWidth(dataOption.ColumnIndex, dataOption.ColumnWidth*256);}//根据数据类型判断显示格式if (propertys[j].PropertyType == typeof (int)){cell.SetCellValue((int)propertys[j].GetValue(Entity[i]));}else if (propertys[j].PropertyType == typeof (decimal) || propertys[j].PropertyType == typeof(double) || propertys[j].PropertyType == typeof(float)){cell.SetCellValue(Convert.ToDouble(propertys[j].GetValue(Entity[i])) );}else{cell.SetCellValue(propertys[j].GetValue(Entity[i]).ToString());}}}//将标题合并if (ShowTitle){IRow rowHead = sheet1.CreateRow(0);ICell cellHead = rowHead.CreateCell(firstColumn);cellHead.SetCellValue(Title);//样式设置IFont font = book.CreateFont();font.FontHeightInPoints = 14;font.IsBold = true;ICellStyle style = book.CreateCellStyle();style.VerticalAlignment = VerticalAlignment.Center;style.Alignment = HorizontalAlignment.Center;style.SetFont(font);cellHead.CellStyle = style;rowHead.HeightInPoints = 20.25f;sheet1.AddMergedRegion(new NPOI.SS.Util.CellRangeAddress(0, 0, firstColumn, lastColumn));}book.Write(ms);ms.Seek(0, System.IO.SeekOrigin.Begin);return ms;}}
}

五、下载文件中文名称出现乱码问题

　　上面第二步，在Excel导出父类中，有这么一句代码

　　context.HttpContext.Response.AddHeader("Content-Disposition", "attachment; filename=" + FullName.EncodingDownloadFileName());

　　其中EncodingDownloadFileName

　　方法是一个String的扩展类，用于将文件名称进行编码，避免出现乱码的情况。

之前测试过程中，在没有使用转码的过程中，发现IE浏览器在下载时，中文名称出现了乱码的情况，其他浏览器正常（这里只测试了IE浏览器、谷歌浏览器、火狐浏览器、QQ浏览器、360浏览器和360极速浏览器）。后来使用了

　　 HttpContext.Current.Server.UrlEncode(filename)对文件名称进行转码后发现，IE浏览器正常了，除了火狐浏览器，其他浏览器都正常。所有就想到当使用火狐浏览器访问时不对名称进行转码，后来写一个String的扩展方法，方便后期其他下载类使用

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;namespace WebSeat.Site.Member.Helper
{/// <summary>/// 说明:String扩展方法/// 创建日期：2016/12/19 9:45:10/// 创建人：曹永承/// </summary>public static class StringHelperExtend{public static string EncodingDownloadFileName(this string filename){if (filename == null){throw new NullReferenceException("filename不能为空");}string agent = HttpContext.Current.Request.Headers["User-Agent"];//如果不是火狐浏览器都进行编码if (agent != null && agent.ToLower().IndexOf("firefox") < 0){return HttpContext.Current.Server.UrlEncode(filename);}return filename;}}
}

六、代码使用

public ActionResult ExportExcel(){//获取数据IList<CityStatics> list = new List<CityStatics>();......ExcelBaseResult<CityStatics> excel = new Excel2003Result<CityStatics>(list, "1.xls", true, "全市各区数据    名称：成都");return excel；}

这样就可以了，看看下载后的excel

补充说明：如果使用gzip压缩方式的，那么文件下载时无法显示文件大小的