Advanced Generics & Constraints

A where clause constrains what a generic type parameter must support — C#'s equivalent of Java's bounded type parameters:

static T Max<T>(T a, T b) where T : IComparable<T> {
    return a.CompareTo(b) > 0 ? a : b;
}

static void PrintAll<T>(List<T> items) where T : class {
    foreach (T item in items) {
        Console.WriteLine(item);
    }
}

Common constraints: where T : IComparable<T> (must support comparison), where T : class (must be a reference type), where T : new() (must have a parameterless constructor).