Question

i am calling Sort on a List:

List<Stuff> list = new List<Stuff>();
list.Sort(StuffSortByName);

with the StuffSortByName declaration of:

private static int StuffSortByName(Stuff x, Stuff y)
{
    ...
}

What surprises me is that my code compiles and works. It’s surprising that no overload of Sort takes a method:

• Sort()
• Sort(Comparison<T>)
• Sort(IComparer<T>)
• Sort(Int32, Int32, IComparer<T>)

So i was fortunate, as i didn’t want to have to create a whole object, that implements IComparer, just to sort stuff. But for the life of me i don’t understand while it compiles.

---

And now i want to duplicate that magic. i want to sort a ListView. But you don’t sort a listivew, you give a listview an IComparer through it’s ListViewItemSorter property:

listView1.ListViewItemSorter = [IComparer]

And, again, i don’t want to write a whole object, i just want to pass a local method (and ideally a non-static one):

listView1.ListViewItemSorter = SortListView;


private static int SortListView(Object x, Object y)
{
    ....
}

Now of course this doesn’t compile because it makes no sense. But then the earlier syntax shouldn’t compile either – but it does.

So it gives me hope that i can have the same confusing syntax here.

How was i allowed to pass a method as a sort comparer in the first case, but not in the second case?

Answer 1

To answer your first question, the reason the method name can be passed is because Comparison<T> is a delegate type, meaning it is a type representing a method signature. See MSDN for details.

In your case, you should either create an IComparer object or have your Stuff object implement IComparable or IComparable<T> (if possible).