Resolving "Could not load type Microsoft.ApplicationServer.Caching.DataCacheSessionStoreProvider"

Published on 02 August 2010 • Estimated reading time: 1 minutes

If you are using AppFabric and decide to swap out the ASP.NET standard caching with it, you may run into the error:

Could not load type "Microsoft.ApplicationServer.Caching.DataCacheSessionStoreProvider"

The error will be pointing to the type of the custom session (line 5 below):

<sessionState mode="Custom" customProvider="AppFabricCacheSessionStoreProvider">
    <providers>
        <!-- specify the named cache for session data -->
        <add name="AppFabricCacheSessionStoreProvider"
             type="Microsoft.ApplicationServer.Caching.DataCacheSessionStoreProvider"
             cacheName="TailSpin" sharedId="TailSpinTravelId"/>
    </providers>
</sessionState>

The cause is that the application can’t find that class. To help it find it, you need to add the following to Configuration → System.Web → Compilation → Assemblies:

<add assembly="Microsoft.ApplicationServer.Caching.Client, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"/>
<add assembly="Microsoft.ApplicationServer.Caching.Core, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"/>