Fix for ASP.NET MVC3 Add Controller – An item with the same key has already been added

Just an interesting little find – so I added a new entity to my EDMX and lo and behold I start getting the “An item with the same key has already been added” when I tried to add a controller – anyway the fix was to remove a couple of rougue navigational properties that had been added automatically!!!!

So if you don’t need them and they are causing this problem – remove them

Dom