Let’s say you have a List of T. And there are Property1, Property2, Property3 in T.
If you want to change the value of Property2 in T then you can use:
var myList = List<T>; foreach (var item in myList) { item.Property2 = newValue; }
or
var myList = List<T>; myList.ForEach(x => x.Proprty2 = newValue);