Page Level Grouping for ASP.NET View State

NCache allows performing ASP.NET View State grouping even at page level. To utilize this feature, the following configurations should be made in Web.config file:

Add the property webAppId in <settings> as follows:

<ncContentOptimization>
   <settings webAppId="CustomerOrderApp"
   enableViewstateCaching="true"
   groupedViewStateWithSessions="true"
   viewstateThreshold="12"
   enableTrace="true"
   maxViewStatesPerSession="10">
      <cacheSettings cacheName = "demoCache">
         <expiration type="Sliding" duration = "300">
      </cacheSettings>
   </settings>
</ncContentOptimization>

Configuration Members

Following is the page level grouping for ASP.NET View State configuration member:

Members Description
webAppId Specifies the webAppId where the application is currently running. When webAppId is specified, NCache looks up for ViewState.xml file to read configurations. If it is not specified, View States will not be grouped and the default settings from Web.config will be used.

ASP.NET View State XML

ViewState.xml is required to configure ASP.NET View State with NCache. This file (ViewState.xml) can be placed in the NCache installation directory %NCHOME%\config (Windows) or /opt/ncache/config (Linux) or in the web application’s bin path.

The webAppId provided in Web.config is matched with the webAppId in ViewState.xml file. Detailed configurations for each group are then loaded from ViewState.xml.

The configurations provided in Web.config are loaded as default settings. The configurations in this .xml file are loaded per group. Here is a sample ViewState.xml file:

<configuration>
  <viewstateConfig>
    <webApp webAppId="CustomerOrderApp">
      <viewstateGroup groupId="Customers" cacheUriMapping="false" enableViewstateCaching="True" viewstateThreshold="12" groupedViewStateWithSessions="false" maxViewStatePerSession="20">
         <cacheSettings cacheName="demoCache" connectionRetryInterval="300">
            <expiration type="Sliding" duration="5"/>
         </cacheSettings>
         <pages>
           <page url="…/Customers.aspx"/> <!—Relative url of a page-->
         </pages>
      </viewstateGroup>
    <viewstateGroup groupId="Orders" cacheUriMapping="false" enableViewstateCaching="true" viewstateThreshold="23" groupedViewStateWithSessions="false" maxViewStatePerSession="5" enableMetadataLocking="True" releaseLockInterval="5">
      <cacheSettings cacheName="demoCache" connectionRetryInterval="300">
        <expiration type="Sliding" duration="20"/>
      </cacheSettings>
          <pages>
            <page url="…/Orders.aspx"/>
            <page url="…/OrderDetails.aspx"/>
          </pages>
     </viewstateGroup>
</webApp>
  <webApp webAppId="ViewStateApp">
    <viewstateGroup groupId="Group_A" enableViewstateCaching="True" viewstateThreshold="2" groupedViewStateWithSessions="false" maxViewStatePerSession="200">
      <cacheSettings cacheName="demoCache">
        <expiration type="Sliding" duration="20"/>
      </cacheSettings>
           <pages>
             <page url="…/viewstate.aspx"/>
           </pages>
      </viewstateGroup>
    </webApp>
  </viewstateConfig>
</configuration>

Configuration Members

Following are the page level grouping for ASP.NET View State configuration member:

Members Description
webApp Used to distinguish multiple web app sections.
viewstateGroup Used to distinguish multiple groups.
pages Relative URL for a page.
Important

Note that all these configuration members are compulsory to be specified.

The following important points should be noted:

  1. The XML file can have multiple web app configurations. In each web app configuration, there can be one or more group configurations.

  2. All the web pages for a certain group are provided in the <pages> section and the page URL is the relative URL of a page.

  3. If a page configuration is not found in the View State configuration file, default settings provided in Web.config will be used.

  4. If any property is missing for any group, the default property value provided in Web.config will be used.

  5. Different caches can also be configured for different groups.

Default and Group Setting Usage

If Web.config provides a web app ID, NCache will look for the ViewState.xml file to read the configuration. In this case, default settings will only be used if the configuration for a page is not found in ViewState.xml or if some optional property is missing in ViewState.xml.

But if Web.config <settings> does not include webAppId, default settings will be used for all View State caching.

Additional Resources

NCache provides a sample application for ViewState on GitHub.

See Also

Configuring and Using NCache Content Optimization
Group View State with Session
Limit View State Caching
Distributed Cache for ASP.NET Output Caching
ASP.NET SignalR Backplane Overview