Page Level Grouping for ASP.NET View State

NCache allows performing 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 = "mycache">
         <expiration type="Sliding" duration = "300">
      </cacheSettings>
   </settings>
</ncContentOptimization>

Configuration Members

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

ViewState.xml

ViewState.xml is required for this feature. This file (ViewState.xml) can be placed at NCache installation config directory %NCHOME%/config (Windows) or opt\ncache\config (Linux) or in the web application’s bin path.

The web application ID provided in Web.config is matched with web application id 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="myCache" 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="replicatedCache" 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="cache">
        <expiration type="Sliding" duration="20"/>
      </cacheSettings>
           <pages>
             <page url="…/viewstate.aspx"/>
           </pages>
      </viewstateGroup>
    </webApp>
  </viewstateConfig>
</configuration>

Configuration Members

Members	Description
`webAppId`	Used to distinguish multiple web app sections.
`GroupId`	Used to distinguish multiple groups.
`page url`	Relative URL for a page.

Important

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

The following important points should be noted:

The XML file can have multiple web app configurations. In each web app configuration, there can be one or more group configurations.
All the web pages for a certain group are provided in <pages> section and page URL is the relative URL of a page.
If a page configuration is not found in View State configuration file, default settings provided in Web.config will be used.
If any property is missing for any group, default property value provided in Web.config will be used.
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 ViewState.xml file to read configuration. In this case, default settings will only be used if 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