c# - Encountered an unexpected error when attempting to resolve tag helper directive '@addTagHelper' -

i'm using visual studio 2015 community edition, , i've created asp.net mvc 5 project.

when open view (index of home or other), shows first 3 lines of page underlined red syntax issue. here error:

encountered unexpected error when attempting resolve tag helper directive '@addtaghelper' value 'microsoft.aspnet.mvc.razor.taghelpers.urlresolutiontaghelper, microsoft.aspnet.mvc.razor'. error: object reference not set instance of object

the screenshot:

when build project, build successfully. when run it, shows lot of errors, runs application.

the type or namespace name 'mvc' not exist in namespace 'microsoft.aspnet' (are missing assembly reference?)

and

'_page_views_home_index_cshtml.executeasync()': no suitable method found override

how can rid of this?

here's how fixed issue:

first, reset visual studio component cache closing visual studio , deleting folder:

c:\users\[username]\appdata\local\microsoft\visualstudio\14.0\componentmodelcache

and finally, check web.config files , change:

<appsettings>     <add key="webpages:version" value="2.0.0.0" />     ... </appsettings> 

to

<appsettings>     <add key="webpages:version" value="3.0.0.0" />     ... </appsettings>