Report Viewer Web Control HTTP Handler未注册问题排查求助

我的Report Viewer功能运行正常，但页面存在一个隐藏div，提示内容如下：

The Report Viewer Web Control HTTP Handler has not been registered in the application's web.config file. Add to the system.web/httpHandlers section of the web.config file, or add to the system.webServer/handlers section for Internet Information Services 7 or later.

项目web.config配置 #

<buildProviders>
  <add extension=".rdlc" type="Microsoft.Reporting.RdlBuildProvider, Microsoft.ReportViewer.WebForms, Version=14.0.0.0, Culture=neutral, PublicKeyToken=89845DCD8080CC91" />
  </buildProviders>
<assemblies>
  <add assembly="Microsoft.ReportViewer.Common, Version=14.0.0.0, Culture=neutral, PublicKeyToken=89845DCD8080CC91" />
  <add assembly="Microsoft.ReportViewer.WebForms, Version=14.0.0.0, Culture=neutral, PublicKeyToken=89845DCD8080CC91" />
</assemblies>


<handlers>
  <add name="ReportViewerWebControlHandler" verb="*" path="Reserved.ReportViewerWebControl.axd" preCondition="integratedMode" type="Microsoft.Reporting.WebForms.HttpHandler, Microsoft.ReportViewer.WebForms, Version=14.0.0.0, Culture=neutral, PublicKeyToken=89845DCD8080CC91" />
</handlers>

<httpHandlers>
  <add path="Reserved.ReportViewerWebControl.axd" verb="*" type="Microsoft.Reporting.WebForms.HttpHandler, Microsoft.ReportViewer.WebForms, Version=14.0.0.0, Culture=neutral, PublicKeyToken=89845DCD8080CC91" validate="false" />
  <add path="Reserved.ReportViewerWebControl.axd" verb="*" type="Microsoft.Reporting.WebForms.HttpHandler, Microsoft.ReportViewer.WebForms, Version=11.0.0.0, Culture=neutral, PublicKeyToken=89845dcd8080cc91" validate="false" />
</httpHandlers>

页面程序集注册代码 #

<%@ Register Assembly="Microsoft.ReportViewer.WebForms, Version=14.0.0.0, Culture=neutral, PublicKeyToken=89845dcd8080cc91"
Namespace="Microsoft.Reporting.WebForms" TagPrefix="rsweb" %>

已尝试的无效解决方法 #

• 将WebForms更新至最新版本并修改对应版本信息
• 移除旧版本的handler配置
• 切换IIS至经典模式（切换后出现500内部服务器错误）

上述方法均未能解决问题，恳请各位帮忙解决该问题。

内容的提问来源于stack exchange，提问作者rujen gelal