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asp.net-mvctag-helpers

Taghelper: Cannot resolve TagHelper containing assembly

I cannot get a custom TagHelper to work in my ASP.NET v5 project. The custom TagHelper is located in the web project itself. I tried following this sample this sample from CodeProject and this tutorial too.

When I try to use the tag without addTagHelper: nothing is transformed, no breakpoints hit in the tag helper.

When I try to @addTagHelper "*, MyWebApplication" to the Viewcomponent, the error is MyWebApplication'. Error: Could not load file or assembly 'MyWebApplication'.

What am I missing?

Tool versions:

Microsoft Visual Studio Enterprise 2015 RC
Version 14.0.22823.1 D14REL
Microsoft .NET Framework Version 4.6.00057
Microsoft.AspNet.Mvc 6.0.0-beta4
Solution

  • The advertised signature for addTagHelper is

    @addTagHelper "className/Filter", "assemblyName"

    Behaviour actually appears to be (at least for helpers in same web project)

    addTagHelper "className/Filter", "folderName"

    because at least into Beta6, the assembly name is the folder name and ignores the attributes in the project properties.

    Here is a sample working demo

    1. Hit F5, view cats.
    2. Edit the project properties to change the assembly name.
    3. Hit F5, view cats. << This should not work?!
    4. Close solution, rename the on disk directory TagHelperDemo -> TagHelperFolderDemo
    5. Observe page fails until the folder name is used for addTagHelper directive

    PS: @addTagHelper is required even when the TagHelper is in the same project. VS2015 re-colours the tag as purple when it is targeted by a TagHelper.