I am getting the red line and shows the title error when I add
@Html.Widget("home_page_top") and
@Html.Action("TopicBlock", "Topic", new { systemName = "HomePageText" })
in nop.web Home view in nopcommerce. And the full error shows the following message i.e. :
Error CS1061 'IHtmlHelper' does not contain a definition for 'Widget' and no accessible extension method 'Widget' accepting a first argument of type 'IHtmlHelper' could be found (are you missing a using directive or an assembly reference?)
I got the solution. I am going in a wrong way I am doing code 3.8 in 4.0. Thats why I am getting this issue.