title: ASPDotNetStoreFront: Unable to cast transparent proxy to type on AddIn
body: <p>I'm having a very odd issue with an old ASPDotNetStoreFront project that we recently redesigned for a client. The redesign went great, but our only AddOn to the project, an in-house created plugin for tax calculation, now will not work. No changes were made to the plugin and I can confirm that it was working up until the redesign. All of our changes to the site were cosmetic in nature. ASPDotNetStoreFront uses an ERP Provider for AddOns <a href="http://manual.aspdotnetstorefront.com/pdf/ASPDNSF%20ERP%20Provider%20SyncV3.pdf%5d" rel="nofollow">as detailed in this PDF</a> I'm familiar with the provider only through this project and have little experience with it elsewhere, which may explain some of my issues with it.</p>
  
  <p>The weird part is that ASPDotNetStoreFront is recognizing that the AddOn exists and fails when attempting to invoke the contract for it. (In this case, it's using ITaxRates and is trying to invoke ITaxRatesContract.) This happens every time I try to activate it and I get
  the following error:</p>
  
  <pre><code>Page URL:/shoppingcart.aspx
  Source:Anonymously Hosted DynamicMethods Assembly
  Message:Unable to cast transparent proxy to type 'AspDotNetStorefront.Contracts.ITaxRatesContract'.
   Stack Trace:
  at ITaxRatesContractToViewHostAdapter_ConstructorInvoker(Object )
  at System.AddIn.Hosting.AddInActivator.AdaptToHost[T](AddInToken pipeline, IContract addInContract)
  at System.AddIn.Hosting.AddInActivator.ActivateInAppDomain[T](AddInToken pipeline, AppDomain domain, AddInControllerImpl controller, Boolean weOwn)
  at System.AddIn.Hosting.AddInActivator.Activate[T](AddInToken token, PermissionSet permissionSet, String appDomainName) 
  at System.AddIn.Hosting.AddInActivator.Activate[T](AddInToken token, AddInSecurityLevel level, String appDomainName)
  at System.AddIn.Hosting.AddInActivator.Activate[T](AddInToken token, AddInSecurityLevel level)
  at System.AddIn.Hosting.AddInToken.Activate[T](AddInSecurityLevel trustLevel)
  at AspDotNetStorefrontCore.AppLogic.UseAddIn[T](Action`1 usageContext) in C:\Users\Username\Documents\Visual Studio 2010\Projects\ASPDNSF\ASPDNSFCore\AppLogic.cs:line 11189 
  </code></pre>
  
  <p>It will find the add on, add it as a token in the core's AppLogic class, sets a variable in ITaxRatesViewToContractAddInAdapter to the Tax Add On and then cause the error above.</p>
  
  <p>Some things of note that happened with this project:</p>
  
  <ul>
  <li><p>This was pulled from our SVN server onto a new laptop, so this is the first time this project has been built on this computer. I don't know if that actually <em>should</em> make a difference, but at this point, I'm willing to go with anything.</p></li>
  <li><p>I've attempted to clean the project, as well as the pipeline the AddIns use to the same results. No luck.</p></li>
  </ul>
  
  <p>I've been racking my head around this one for the last day and it's getting on my last nerve. Any help would be super mega ultra appreciated. Thanks!</p>