Document Viewer for ASP.NET Web Forms Requirements and Limitations

Aug 18, 2023
3 minutes to read

Document Viewer Requirements

Required Libraries

The Web Document Viewer requires the following libraries:

Third-party Libraries
- jQuery 3.4.1+ (The recommended version is jQuery 3.5.1+.)
- knockout 3.5.1+
DevExtreme Libraries

DevExtreme libraries are used to render UI elements in Web reporting components.

To include these script libraries in a client application, do one of the following:

Automatic Integration

Add the resources section to the application’s Web.config file to include client-side libraries on the web page:

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

Manual Integration

Follow the setps below:
1. Declare an empty resources section in the Web.config file. This prevents a control from loading libraries automatically when libraries are already referenced on the web page.
  - XML
```
<resources>
</resources>
```
  If you remove the DevExpress resources section from the Web.config file, the DevExtreme libraries are loaded automatically. For more information, review the following help topic: External Client Libraries.
2. Add the package.json npm configuration file with the following contents:
  - package.json
```
{
    "version": "1.0.0",
    "name": "asp.net",
    "private": true,
    "dependencies": {
        "devextreme-dist": "23.2.*",
        "devexpress-reporting": "23.2.*"
    }
}
```
3. Right-click package.json in the Solution Explorer and select Restore Packages. Alternatively, you can execute the following comand in the folder that contains the package.json file:
```
npm install
```
4. Attach the following scripts and stylesheets to the <head> section of the page:
  - HTML
```
<html>
<head>
...
<link href="node_modules/devextreme-dist/css/dx.light.css" type="text/css" rel="Stylesheet" />
<link href="node_modules/devexpress-reporting/dist/css/dx-webdocumentviewer.css" type="text/css" rel="Stylesheet" />

<script src="node_modules/jquery/dist/jquery.min.js" type="text/javascript"></script>
<script src="node_modules/knockout/build/output/knockout-latest.js" type="text/javascript"></script>

<script src="node_modules/devextreme-dist/js/dx.all.js" type="text/javascript"></script>
...
</head>
...
</html>
```
  The load order is important.

For a list of supported web browsers, refer to the following help topic: Supported Browsers.

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.

<system.web>
...
  <httpHandlers>
    ...
    <add type="DevExpress.Web.ASPxHttpHandlerModule, DevExpress.Web.v23.2, Version=23.2.5.0, Culture=neutral, PublicKeyToken=b88d1754d700e49a" 
         verb="GET,POST" path="DXXRDV.axd" validate="false" />
  </httpHandlers>  
  <httpModules>
    <add type="DevExpress.Web.ASPxHttpHandlerModule, DevExpress.Web.v23.2, Version=23.2.5.0, Culture=neutral, PublicKeyToken=b88d1754d700e49a" name="ASPxHttpHandlerModule" />
  </httpModules>
</system.web>
<system.webServer>
  <handlers>
    ...
    <add type="DevExpress.Web.ASPxHttpHandlerModule, DevExpress.Web.v23.2, Version=23.2.5.0, 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.v23.2, Version=23.2.5.0, 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#
VB.NET

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

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.

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Document Viewer Requirements

Required Libraries

Register HTTP Handlers

Document Viewer Limitations