Handling Missing Assembly Reference Errors after Generating ASP.NET Web API or WCF OData v3 Services with Services Wizard

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AUTHOR: Doroteya Agayna

DATE POSTED: February 26, 2014

PROBLEM

After you generate a new ASP.NET Web API or WCF OData v3 service with Services Wizard, the project that hosts its code base is unbuildable due to missing assembly references. The build errors you will observe are as follows:

 

ASP.NET Web API
  • The type or namespace name 'Http' does not exist in the namespace 'System.Web'. 
  • The type or namespace name 'HttpResponseMessage' could not be found.
  • The type or namespace name 'Newtonsoft' could not be found.
Note that if you have generated the ASP.NET Web API service in a project, which targets .NET Framework 4.0, you will experience the same errors. In this case, you can solve them with the help of the workflow described in the How to: Intall Web API NuGet Package on .NET Framework 4.0 article.

 

WCF OData v3
  • The type or namespace name 'Services' does not exist in the namespace 'System.Data'.
  • The type or namespace name 'ServiceOperation' could not be found.
  • The type or namespace name 'ResourceType' could not be found.
  • The type or namespace name 'ResourceSet' could not be found.
  • The type or namespace name 'DataService' could not be found.

 

DESCRIPTION

Versions 2.8.* of NuGet Package Manager introduced a breaking change in the API used by Services Wizard until Q1 2014. If you have a previous version of the manager on the Visual Studio instance you use, with Telerik Data Access Q1 2014 or later, the change prevents the wizard from installing the packages required by the generated Web API and OData v3 services. The same limitation appears, if the package manager on the Visual Studio instance is the latest version, but the version of Telerik Data Access is earlier then Q1 2014.

SOLUTION

To resolve the errors and successfully build the generated ASP.NET Web API or WCF OData v3 services, you can choose between one of the following approaches:

  • Upgrade of Telerik Data Access to version Q1 2014 or later – this solution is suitable when the version of NuGet Package Manager is 2.8 or later. More details about the process are provided in the Installing Telerik Data Access article.
  • Upgrade of NuGet Package Manager to version 2.8 or later - this is applicable in case the version of Telerik Data Access is Q1 2014 or later. Additional information about how to find out which version of NuGet Package Manager is utilized, and how to upgrade it is available in this article.
  • Manual installation of the necessary packages through Package Manager Console – this solution is useful when neither of the previously suggested upgrades is possible.
In case the first and the second options are feasible to you, make sure to generate the service through Services Wizard again, after the installation processes are complete.

If you need to install the necessary packages manually in the project that hosts the code base for the generated service, you can run the corresponding commands in Package Manager Console:

ASP.NET Web API 
Get-Project <project_name> | Install-Package Microsoft.AspNet.WebApi

WCF OData v3
Get-Project <project_name> | Install-Package Microsoft.Data.Services

Once the packages are installed, you can build your application.

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