Webform中，生成Excel，一般是设置response.Content.Headers.ContentType输出类型为application/vnd.ms-excel,思路都是这样的。

每一个API方法都这样做一下，也是可以的。参考：http://www.cnblogs.com/jizhong/p/3592088.html

 

更好的做法是，客户端请求的时候，设置Requst.Header的Accept:application/vnd.ms-excel。目的：客户端设置了什么类型，服务端针对性的去调用相应方法，返回相应类型的文件流，可配置，可扩展，Formatter相关不写死在具体方法中，剥离出来。

var _exportToExcel = function (clientId) {	        var url = serviceBase + 'api/clientStatusLog?clientId='+clientId;	        return $http.get(url, { headers: { Accept: 'application/vnd.ms-excel' }, responseType: 'arraybuffer' }).then(function (response) {	            return response;	        });	    }

 

服务端在WebApiConfig中添加一种Formatter,我们添加自己写的类的对象，类继承自System.Net.Http.Formatting.BufferedMediaTypeFormatter的MediaTypeFormatter。类中重写了父类的CanWriteType，设置type == typeof(ClientStatusLogReportDto)或者IEnumerable<ClientStatusLogReportDto>时候，CanWriteType方法返回true. 这样在Controller方法中，直接return ClientStatusLogReportDto或List<ClientStatusLogReportDto>, 自己写的Formatter方法会进行生成Excel的逻辑，调用重写父类的WriteToStream等方法，实现生成指定格式的数据，返回响应。

　

public static class WebApiConfig    {        public static void Register(HttpConfiguration config)        {            // Formatters            config.Formatters.Add(new ClientExcelormatter());            config.Formatters.Add(new ClientStatusLogExcelormatter());        }   }

　　

public class ClientStatusLogExcelormatter: BufferedMediaTypeFormatter    {        private const string MIME_TYPE = "application/vnd.ms-excel";        private HSSFWorkbook workBook;        public ClientStatusLogExcelormatter()        {            // Add the supported media type.            SupportedMediaTypes.Add(new MediaTypeHeaderValue(MIME_TYPE));                }        public override bool CanWriteType(System.Type type)        {            if (type == typeof(ClientStatusLogReportDto))            {                return true;            }            else            {                Type enumerableType = typeof(IEnumerable
     
      );                return enumerableType.IsAssignableFrom(type);            }        }        public override void WriteToStream(Type type, object value, Stream writeStream, HttpContent content)        {            var clientList = value as IEnumerable
      
       ;            var curRole = OwinContextHelper.GetUserRole();                       if (clientList != null)            {                Initialize();                GenerateData(clientList);                workBook.Write(writeStream);            }            else            {                var singleObj = value as ClientStatusLogReportDto;                if (singleObj == null)                {                    throw new InvalidOperationException("Cannot serialize type");                }            }            var filename = "clientStatusLog.xls";            content.Headers.ContentType = new MediaTypeHeaderValue(MIME_TYPE);            content.Headers.Add("x-filename", filename);            content.Headers.ContentDisposition = new System.Net.Http.Headers.ContentDispositionHeaderValue("attachment");            content.Headers.ContentDisposition.FileName = filename;        }        private void Initialize()        {            workBook = new HSSFWorkbook();            create a entry of DocumentSummaryInformation            DocumentSummaryInformation dsi = PropertySetFactory.CreateDocumentSummaryInformation();            dsi.Company = "Centria Healthcare";            workBook.DocumentSummaryInformation = dsi;            create a entry of SummaryInformation            SummaryInformation si = PropertySetFactory.CreateSummaryInformation();            si.Subject = "Client Status Log Export";            workBook.SummaryInformation = si;        }        private void GenerateData(IEnumerable
       
         clientList)        {            HSSFSheet oHSSFSheet = (HSSFSheet)workBook.CreateSheet("Client List");            //====================================            string[] columnList = { "Name", "Funding Source", "Current Status", "Status", "Timestamp", "Creator", "Updater"};            int colCount = columnList.Length;            int rowNum = 0;            int colNum = 0;            IFont fontHeader = workBook.CreateFont();            fontHeader.FontName = "Arial";            fontHeader.Boldweight = (short)FontBoldWeight.Bold;                        fontHeader.FontHeightInPoints = 10;            IFont fontRow = workBook.CreateFont();            fontRow.FontName = "Arial";            fontRow.FontHeightInPoints = 10;            HSSFCellStyle headerStyle = (HSSFCellStyle)workBook.CreateCellStyle();            HSSFCellStyle normalRowStyle = (HSSFCellStyle)workBook.CreateCellStyle();            headerStyle.SetFont(fontHeader);            headerStyle.BorderBottom = BorderStyle.Thin;            headerStyle.BorderLeft = BorderStyle.Thin;            headerStyle.BorderRight = BorderStyle.Thin;            headerStyle.BorderTop = BorderStyle.Thin;            headerStyle.Alignment = HorizontalAlignment.Center;            headerStyle.VerticalAlignment = VerticalAlignment.Center;            headerStyle.FillForegroundColor = HSSFColor.Black.Index;            normalRowStyle.SetFont(fontRow);            normalRowStyle.BorderBottom = BorderStyle.Thin;            normalRowStyle.BorderLeft = BorderStyle.Thin;            normalRowStyle.BorderRight = BorderStyle.Thin;            normalRowStyle.BorderTop = BorderStyle.Thin;            normalRowStyle.Alignment = HorizontalAlignment.Center;            normalRowStyle.VerticalAlignment = VerticalAlignment.Center;            normalRowStyle.FillForegroundColor = HSSFColor.Black.Index;            HSSFRow header = (HSSFRow)oHSSFSheet.CreateRow(0);            for (int i = 0; i < colCount; i++)            {                HSSFCell oCell = (HSSFCell)header.CreateCell(i);                oCell.SetCellType(CellType.String);                oCell.SetCellValue(columnList[i]);                oCell.CellStyle = headerStyle;            }                       //write each item.            foreach (ClientStatusLogReportDto client in clientList)            {                HSSFRow dataRow = (HSSFRow)oHSSFSheet.CreateRow(++rowNum);                colNum = 0;                foreach (PropertyInfo proInfo in typeof(ClientStatusLogReportDto).GetProperties())                {                    object v = proInfo.GetValue(client);                    string value = string.Empty;                    if (v != null)                    {                        value = v.ToString();                    }                    HSSFCell cell = (HSSFCell)dataRow.CreateCell(colNum++);                    cell.SetCellType(CellType.String);                    cell.SetCellValue(value);                    cell.CellStyle = normalRowStyle;                                    }            }        }        public override bool CanReadType(Type type)        {            return false;        }            }
       
      
     

public class ClientStatusLogController : ApiController    {        private readonly IClientStatusLogService _clientStatusLogService;        private readonly IMembershipService _membershipService;        public ClientStatusLogController(IClientStatusLogService clientStatusLogService, IMembershipService membershipService)         {            this._clientStatusLogService = clientStatusLogService;            this._membershipService = membershipService;        }        public List
     
       GetList(Guid clientId)        {            var list = _clientStatusLogService.GetList(clientId);            var listDto = new List
      
       ();            foreach (var item in list)            {                var dto = Mapper.Map
       
        (item);                dto.CreatedBy = _membershipService.GetUserRealName(dto.CreatedBy);                dto.CreatedBy = _membershipService.GetUserRealName(dto.ModifiedBy);                listDto.Add(dto);            }            return listDto;        }    }