C# - Get the item type for a generic list

Question

What would be the best way of getting the type of items a generic list contains? It\'s easy enough to grab the first item in the collection and call .GetType(), but I can\'

Answer 1

Here is a solution that also works with derived classes.

Because with this class :

  public class SubList : List
  {   }

If you call : subList.GetType().GetGenericArguments().Single()

It will throws a System.InvalidOperationException

With this method it works for derived classes :

public Type GetListItemType(List list)
{
  Type type = list.GetType();
  while (type != typeof(List))
    type = type.BaseType;
  return type.GetGenericArguments().Single();
}


var list = new List();
var subList = new SubList();
Console.WriteLine(GetListItemType(list)); // System.Int32
Console.WriteLine(GetListItemType(subList)); // System.Int32