Type or namespace name does not exist

c# .net visual-studio-2010 visual-studio
Attilah picture Attilah · Apr 6, 2011 · Viewed 510.3k times · Source

I have a WCF Data Service project built with Visual Studio 2010, which was working fine. All of a sudden, it didn't compile anymore. It was giving me messages like:

Error 7 The type or namespace name 'Services' does not exist in the namespace 'System.Data' (are you missing an assembly reference?) C:\U...s\Visual Studio 2010\Projects...\DataService.cs ...

Error 8 The type or namespace name 'Linq' does not exist in the namespace 'System' (are you missing an assembly reference?) DependencyResolver.cs 3 14

Error 10 The type or namespace name 'Web' does not exist in the namespace 'System.ServiceModel' (are you missing an assembly reference?)

Error 12 The type or namespace name 'DataService' could not be found (are you missing a using directive or an assembly reference?)

How can I fix it?

Answer

Nathan Koop picture Nathan Koop · Aug 23, 2011

I have had the same problem, and I had to set the "Target Framework" of all the projects to be the same. Then it built fine. On the Project menu, click ProjectName Properties. Click the compile tab. Click Advanced Compile Options. In the Target Framework, choose your desired framework.

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