ASP.NET MVC - How to load static code (content) from another class or control?

Question

I am new to MVC and I can't seem to find the answer I am looking for, probably because of not using the correct terminology to search.

I am trying to load a static menu navigation in my ASP.NET MVC View (which is a widget template in Sitefinity CMS).

In Web Forms, this was an easy task by registering a User Control in the widget template like this:

<%@ Register TagName="SecNav" TagPrefix="CustomNav" Src="~/CustomWidgets/SecondaryNav.ascx" %>

And then in the body of my Widget template I could call the control like this:

<ul>
  <CustomNav:SecNav runat="server" />
</ul>

What is the equivalent method of the above in ASP.NET MVC View?