Failed to compare two elements in the array

Question

I have a List where T is a class that exposes a "Username" property. Username is of a custom type that encapsulates a string. I implemented the IComparable<T> interface on this custom type that simply returns

this.encapsulatedString.CompareTo(other.encapsulatedString)

I defined an ICollectionView of the List thus:

AllUsers=CollectionViewSource.GetDefaultView(myList);

I added a Sortdescription:

AllUsers.SortDrscriptions.Add(new SortDescription("Username",ListSortDirection.Ascending));

On this line the code throws the exception stated in the title. I can sort the list by other means without problem. Where is the exception coming from?

Answer 1

Stupidstupidstupid: The custom type has to implement IComparable as well as IComparable<T> It seems the SortDescription uses the old fashioned non-generic version of CompareTo

I am going to get some much needed sleep...

Answer 2

As you said, you need to implement the non-generic IComparable. You can use the Comparer<T> class if you want to implement this interface in a nice generic way :)