在ASP.NET MVC 无需Web Form和Report Viewer 预览SSRS报表解决方案...

      环境

      ASP.NET MVC 4.0 SQL Server Reporting Services

      需求

      在保存报表为文件（如PDF）之前，可以预览报表（支持图片）。

      分析

      网络上的解决方案，都是告诉你用最原始的办法：结合ASP.NET Web Form Report Viewer控件。因为SQL Server Reporting Services (SSRS) 只有Web Form的Report Viewer控件，没对ASP.NET MVC进行特别支持。

      我们不能直接在ASP.NET MVC用Report Viewer是因为Report Viewer依赖View State，而View State正是MVC要解决的问题。。。

      因为不满意这种整合Web Form的解决方案，今晚思考了一下，既然SSRS支持渲染结果为MHTML（MIME HTML），那么，如果我们解决浏览器不显示MHTML内容（需要另存再本地打开），就可以实现预览的办法：先渲染成MHTML，再解释MIME，再把图片附件转成data嵌入。

      步骤

1. 设计页面

      因为预览结果是完整的HTML，我在报表页面嵌入了一个iframe。。。。。。src指向一个Web API，该Web API会返回渲染后的html内容（包括图片）。

2. 下载文件

      添加一个Web API 函数，用以渲染MHTML并返回text/html结果。为了简化操作，我把报表参数拼接起来，键值用“|”分隔，参数用“`”分隔。实际使用请根据自己的情况修改。。。

      publicHttpResponseMessage DownloadReportContent(stringReportFileName, stringParameters)

      {

      varparameters = newDictionary<string, string>();

      Parameters.Split('`').ForEach(p =>

      {

      varparts = p.Split('|');

      parameters.Add(parts[0], parts[1]);

      });

      byte[] reportContent;

      stringfileExtension, mimeType;

      ReportGenerator.GenerateReport('ReportServer', 'ReportServerExecutionURL', 'ReportServerUserName', 'ReportServerPassword', 'ReportServerDomain', ReportFileName, ExportFormat.MHTML, parameters, string.Empty, outreportContent, outfileExtension, outmimeType);

      reportContent = ReportConvertor.Convert(reportContent);

      varresultStream = newSystem.IO.MemoryStream(reportContent);

      resultStream.Position = 0;

      varresponse = newHttpResponseMessage();

      response.StatusCode = HttpStatusCode.OK;

      response.Content = newStreamContent(resultStream);

      returnresponse;

      }

3. 渲染报表为MHTML

      下面的方法可以用作渲染其它格式，如最常见的PDF

      usingSystem;

      usingSystem.Collections.Generic;

      usingSystem.Linq;

      usingSystem.Security.Principal;

      //using YOUR_IMPORTED_WEB_REFERENCE_FOR_SSRS_EXECUTION_SERVICE_HERE

      namespaceOrg.SSRSPreview

      {

      /// <summary>

      /// Export Formats

      /// </summary>

      publicenumExportFormat

      {

      /// <summary>XML</summary>

      XML,

      /// <summary>Comma Delimitted File

      CSV,

      /// <summary>TIFF image</summary>

      Image,

      /// <summary>PDF</summary>

      PDF,

      /// <summary>HTML (Web Archive)</summary>

      MHTML,

      /// <summary>HTML 4.0</summary>

      HTML4,

      /// <summary>HTML 3.2</summary>

      HTML32,

      /// <summary>Excel</summary>

      Excel,

      /// <summary>Word</summary>

      Word

      }

      publicclassReportGenerator

      {

      /// <summary>

      /// Gets the string export format of the specified enum.

      /// </summary>

      /// <param name='Format'>export format enum</param>

      /// <returns>enum equivalent string export format</returns>

      privatestringGetExportFormatString(ExportFormat Format)

      {

      switch(Format)

      {

      caseExportFormat.XML: return'XML';

      caseExportFormat.CSV: return'CSV';

      caseExportFormat.Image: return'IMAGE';

      caseExportFormat.PDF: return'PDF';

      caseExportFormat.MHTML: return'MHTML';

      caseExportFormat.HTML4: return'HTML4.0';

      caseExportFormat.HTML32: return'HTML3.2';

      caseExportFormat.Excel: return'EXCEL';

      caseExportFormat.Word: return'WORD';

      default:

      return'PDF';

      }

      }

      /// <summary>

      /// generate a report

      /// </summary>

      /// <param name='ReportServer'>report server</param>

      /// <param name='ReportServerExecutionURL'>rendering execution url of report server</param>

      /// <param name='ReportServerUserName'>user name to access report server</param>

      /// <param name='ReportServerPassword'>password of the user name</param>

      /// <param name='ReportServerDomain'>domain of the report server (for active directory)</param>

      /// <param name='ReportServerSubDir'>folder of the report in the report server</param>

      /// <param name='FileFormat'>output of the report</param>

      /// <param name='Parameters'>parameters for the report</param>

      /// <param name='ReportContent'>rendered report content</param>

      /// <param name='FileExtension'>file extension of the report</param>

      /// <param name='MimeType'>mime type of the generated file</param>

      publicvoidGenerateReport(stringReportServer,

      stringReportServerExecutionURL,

      stringReportServerUserName,

      stringReportServerPassword,

      stringReportServerDomain,

      stringReportServerSubDir,

      stringReportFileName,

      ExportFormat FileFormat,

      Dictionary<string, string> Parameters,

      stringDeviceInfo,

      outbyte[] ReportContent,

      outstringFileExtension,

      outstringMimeType)

      {

      using(varreportExecutionService = newReportExecutionService.ReportExecutionServiceSoapClient('ReportExecutionServiceSoap', ReportServerExecutionURL))

      {

      reportExecutionService.ClientCredentials.Windows.AllowedImpersonationLevel = TokenImpersonationLevel.Impersonation;

      reportExecutionService.ClientCredentials.UserName.UserName = ReportServerUserName;

      reportExecutionService.ClientCredentials.UserName.Password = ReportServerPassword;

      reportExecutionService.ClientCredentials.Windows.ClientCredential = newSystem.Net.NetworkCredential(ReportServerUserName, ReportServerPassword, ReportServerDomain);

      varparameters = Parameters.Select(p => newParameterValue { Name = p.Key, Value = p.Value }).ToList();

      // Init Report to execute

      ServerInfoHeader serverInfoHeader;

      ExecutionInfo executionInfo;

      ExecutionHeader executionHeader = reportExecutionService.LoadReport(null, ReportFileName, null, outserverInfoHeader, outexecutionInfo);

      // Attach Report Parameters

      reportExecutionService.SetExecutionParameters(executionHeader, null, parameters.ToArray(), null, outexecutionInfo);

      // Render

      stringencoding;

      Warning[] warnings;

      string[] streamIds;

      reportExecutionService.Render(executionHeader, null, GetExportFormatString(FileFormat), DeviceInfo, outReportContent, outFileExtension, outMimeType, outencoding, outwarnings, outstreamIds);

      }

      }

      }

      }