Error in Web Site project: "Failed to setup service. System.InvalidCastException: Unable to cast COM object of type 'System.__ComObject' to class type 'Telerik.Reporting.Vs.Common.AssemblyReference'."

RELATED TO:

AUTHOR: Stephania Tapela

DATE MODIFIED : October 16, 2017

DATE POSTED: February 20, 2017

Article information
Related to

Telerik Reporting
Type of project

Web Site

Created by

Stef, Telerik

Last modified

February 20, 2017

Last modified by

Stef,Telerik


PROBLEM
On attempt to add a Report Viewer control on the design surface of a WebForm, there is an error in Web Site projects.

For example, on an attempt to drag the HTML5 ASP.NET WebForms ReportViewer from VS Toolbox onto a WebForm.aspx in Design mode:
Failed to setup service.
System.InvalidCastException: Unable to cast COM object of type 'System.__ComObject' to class type 'Telerik.Reporting.Vs.Common.AssemblyReference'. Instances of types that represent COM components cannot be cast to types that do not represent COM components; however they can be cast to interfaces as long as the underlying COM component supports QueryInterface calls for the IID of the interface.
   at Telerik.Reporting.Vs.Common.DTEReferences.WebSiteReferences.Contains(String assemblyName)
   at Telerik.Reporting.Vs.Common.DTEReferences.WebSiteReferences.Contains(AssemblyName assemblyName)
   at Telerik.ReportViewer.Html5.WebForms.Design.InitialConfigHelper.ConfigureReferences(DTEProject project)
   at Telerik.ReportViewer.Html5.WebForms.Design.InitialConfigHelper.ConfigureFirstTime(IServiceProvider serviceProvider)


SOLUTION
Web Site projects handle assembly references differently, which is the major reason Telerik Reporting not to provide design time support for Web Site projects.

The recommended approach is to use reports designed with the Standalone Report Designer, or reports from an external assembly referenced by the Web Site project. Report Viewers have to be configured manually in Web Site projects:
  • HTML5 Javascript Viewer Manual Setup
  • HTML5 ASP.NET MVC Viewer Manual Setup
  • HTML5 ASP.NET WebForms Viewer Manual Setup


    Note    : The automatic upgrade feature is not designed to work with Web Site projects as well. Web Site projects must be upgraded manually - Upgrading Telerik Reporting Projects.

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