Question

I’m looking for the best way to make it possible to get a random element from a List where the T’s will be objects of different types that is not related via a base class.

I’ve been loooking at creating an extension method to List, or a helper method that recieves a List, but I haven’t been able to get it together. Each time I’ve run into problems handling a T that I don’t know what is.

Is it possible to do this without making an interface or a base class? Because I can’t see any meaningful way of implementing a base class or interface for the different T’s.

Regards
Jesper Hauge

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After some more reading about generic methods I managed to write some code myself. This is my solution:

public static class ListExt
{
    public static T RandomItem<T>(this List<T> list)
    {
        if (list.Count == 0)
            return default(T);
        if (list.Count == 1)
            return list[0];
        Random rnd = new Random(DateTime.Now.Millisecond);
        return list[(rnd.Next(0, list.Count))];
    }
}

It’s an extension method that enables selecting a random item from any List with the following code:

private Picture SelectTopPic()
{
    List<Picture> pictures = GetPictureList();
    return pictures.RandomItem();
}

Answer 1

Ended up going with an extension method, shown as an appendix to the original post.

.Hauge