public Action(
UndoRedoList <T> owner,
Operation operation,
int index,
T item)
{
this.owner = owner;
this.operation = operation;
this.index = index;
this.item = item;
}
public UndoRedoItem(UndoRedoList <T> owner, int index, T instance) :
base(instance)
{
this.owner = owner;
this.index = index;
}