Document Viewer for ASP.NET Web Forms Requirements and Limitations

• Jul 18, 2024
• 2 minutes to read

Document Viewer Requirements

Required Libraries

Web Reporting components require DevExtreme and third-party libraries, which you can register automatically. To do this, add the resources section to the application’s Web.config file:

XML

<devExpress>
    <!-- ... -->
    <resources>
        <add type="ThirdParty" />
        <add type="DevExtreme" />
    </resources>
</devExpress>

For manual registration, review the following help topic: Client Script Libraries.

Register HTTP Handlers

Register ASPxHttpHandlerModule (DXXRDV.axd) in the web.config file as a module to process resources and as a handler to process data.

The ASPxHttpHandlerModule is automatically registered in this file in the following cases:

• When you use DevExpress project templates to create an application with reporting controls;
• When the Visual Studio Designer opens a page with the Document Viewer in markup.

If you create the Document Viewer in code, you should register ASPxHttpHandlerModule explicitly. Insert the declarations in the system.web/httpModules and system.webServer/modules configuration sections, and add the handler registration to the system.web/httpHandlers and system.webServer/handlers sections.

XML

<system.web>
...
  <httpHandlers>
    ...
    <add type="DevExpress.Web.ASPxHttpHandlerModule, DevExpress.Web.v24.2, Version=24.2.5.0, Culture=neutral, PublicKeyToken=b88d1754d700e49a" 
         verb="GET,POST" path="DXXRDV.axd" validate="false" />
  </httpHandlers>  
  <httpModules>
    <add type="DevExpress.Web.ASPxHttpHandlerModule, DevExpress.Web.v24.2, Version=24.2.5.0, Culture=neutral, PublicKeyToken=b88d1754d700e49a" name="ASPxHttpHandlerModule" />
  </httpModules>
</system.web>
<system.webServer>
  <handlers>
    ...
    <add type="DevExpress.Web.ASPxHttpHandlerModule, DevExpress.Web.v24.2, Version=24.2.5.0, Culture=neutral, PublicKeyToken=b88d1754d700e49a" 
         verb="GET,POST" path="DXXRDV.axd" name="ASPxWebDocumentViewerHandlerModule" preCondition="integratedMode" />
  </handlers>
  <modules runAllManagedModulesForAllRequests="true">
    <add type="DevExpress.Web.ASPxHttpHandlerModule, DevExpress.Web.v24.2, Version=24.2.5.0, Culture=neutral, PublicKeyToken=b88d1754d700e49a" name="ASPxHttpHandlerModule" />
  </modules>
</system.webServer>

The Document Viewer validates the configuration and displays the following error message if the corresponding handlers are not registered.

“The DXXRDV.axd handler is not registered in the web.config (section: system.webServer/handlers). To disable web.config validation, use the DevExpress.XtraReports.Web.ASPxWebDocumentViewer.DisableHttpHandlerValidation property.“

Do not use handlers and/or validate their registration in the following cases:

• You use custom HTTP handlers or MVC controllers to process requests.
• Handlers are registered in the <location> section, and automatic validation fails.

To disable automatic handler validation, set the DisableHttpHandlerValidation property to true.

C#

protected void Page_Load(object sender, EventArgs e) {
    ASPxWebDocumentViewer1.DisableHttpHandlerValidation = true;
}

VB.NET

Protected Sub Page_Load(sender As Object, e As EventArgs)
    ASPxWebDocumentViewer1.DisableHttpHandlerValidation = True
End Sub

Document Viewer Limitations

• The following document formats do not support export to multiple files:

  • HTML;
  • Image;
  • XLS;
  • XLSX.

  You can export a report to any of these formats as a single file or as a single file page-by-page (one file that contains multiple pages).

• The Document Viewer prints a report by converting it to PDF and printing the PDF. This approach requires browser support for PDF.