'ExtensionAttribute' is ambiguous in the namespace 'System.Runtime.CompilerServices' RRS feed

  • Question

  • hi,

    Im using .net framework 2.0. recently i added the third party dll LINQBRIDGE.DLL in my project for implementing linq operations.

    now when i build the project im getting the below error:

    error bc30560 'ExtensionAttribute' is ambiguous in the namespace 'System.Runtime.CompilerServices'.

    i think the other projects are not compatible with this third party dll. please let me know how can i resolve this error when i add linqbridge.dll

    Friday, July 28, 2017 5:32 PM

All replies

  • Does the error message say which assemblies define ExtensionAttribute? If one of those assembles is built from a project of yours, then delete the definition of class ExtensionAttribute from that project and instead add a reference to LINQBRIDGE.DLL. Perhaps add a TypeForwardedToAttribute, as well.

    (In C#, one can sometimes solve ambiguity errors by giving one of the assemblies an extern alias. In the command-line C# compiler, that would be the /reference:alias=filename syntax. However, you seem to be using Visual Basic, and it looks like the /reference option of the Visual Basic compiler does not support anything similar.)

    Friday, July 28, 2017 6:04 PM
  • No it didnt specify the assembly name
    Friday, July 28, 2017 7:30 PM
  • Hi umamaheshwaran ganesan,

    Based on your description and related error message, it seems that 3rd-party dll file cause the issue, I would suggest that you could connect the 3rd-party DLL author for suitable support.


    Thanks for your understanding.

    Best regards,


    MSDN Community Support
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    Monday, July 31, 2017 2:50 AM