I tried with code you provided me, but i am getting below error.
Telerik.Sitefinity.Pages.Model.PageNode, Telerik.Sitefinity.Model was not granted View in Pages for principals with IDs 00000000-0000-0000-0000-000000000000
I repalce my code with following line of code. Error is coming at this line only.
.WorkWith().Pages().Where(Function(p) p.ShowInNavigation = True).Get().ToList