如何从与委托c＃

Question

我有一个方法，它将一个委托作为参数（比如说动作），将其设置为null。当我使用参数调用该方法时，我需要通过调用该委托从列表中选择与该委托匹配的元素。当我没有传递委托作为参数时，它需要考虑该列表的所有元素。

public List<Reducere> Reduceri { get; set; }

public void AplicaReduceri(Func<Reducere, string> selector = null)
{
    if (selector != null)
    {
         //here I need to select a Reducere from the list 
         //that matches that delegate by invoking the delegate
    }
    else
    {
         //here I need to take in consideration all the elements of that list
    }
}