I don't believe there is a way to do this using Orchard's Navigation provider alone. I've done something similar, but I had to handle the tertiary level separately, and implement the menu UI myself from my own controller.
You will still need to add the third level in your module's Navigation Provider, as this will then mark the LHS menu and Tab selections correctly. Something along the lines of:
namespace Company.MyModule {
public class TileSortAdminMenu : INavigationProvider {
private Localizer T { get; set; }
public string MenuName { get { return "admin"; } }
public void GetNavigation(NavigationBuilder builder) {
builder
.AddImageSet("mymodule")
.Add(T("My Module"), "5", menu => menu
.LinkToFirstChild(true)
.Add(T("Content Item 1"), "1", item => item
.LocalNav()
.LinkToFirstChild(true)
.Add(T("Tab 1"), "1", tab => tab
.LocalNav()
.Action("Index", "MyModuleAdmin", new { area = "Company.MyModule"})
)
.Add(T("Tab 2"), "2", tab => tab
.LocalNav()
.Action("Tab2", "MyModuleAdmin", new { area = "Company.MyModule"})
)
)
.Add(T("Content Item 2"), "2", item => item
.LocalNav()
.LinkToFirstChild(true)
.Add(T("Tab 1"), "1", tab => tab
.LocalNav()
.Action("ContentItem2Tab1", "MyModuleAdmin", new { area = "Company.MyModule"})
)
.Add(T("Tab 2"), "2", tab => tab
.LocalNav()
.Action("ContentItem2Tab2", "MyModuleAdmin", new { area = "Company.MyModule"})
)
)
);
}
}
}
In your View, you can maintian Orchard's styling by using something like:
<ul class="localmenu localmenu-submenu">
<li class="selected"><a href="@Url.Action("Index", "MyModuleAdmin", new { area = "Company.MyModule"})">Tab 1</a<</li>
<li><a href="@Url.Action("Tab2", "MyModuleAdmin", new { area = "Company.MyModule"})">Tab 2</a></li>
</ul>
Where the class localmenu-submenu
is a styling hook for your own style tweaks, and you add the class selected
to whichever tab you're viewing.
Alternatively, depending on what you're trying to achieve, you could just implement jQuery UI's Tabs (available through the Orchard.jQuery resource manifest), and just update the styling to look Orchard-y.