List<int> value = new List<int>(4);
//此时 Count:0 Capacity: 4
            
for (int i = 1; i <= 5; i++)
{
    value.Add(i);
}
//此时 Count:5 Capacity: 8            

value.TrimExcess();
//此时 Count:5 Capacity: 5
            

//remove an item
value.RemoveAt(4);
//此时 Count:4 Capacity: 5
value.TrimExcess();
//此时 Count:4 Capacity: 5---------------[color=#FF0000]Capacity为什么不是4呢？请高手指点[/color]
//remove another item
value.RemoveAt(1);
//此时 Count:3 Capacity: 5
value.TrimExcess();
//此时 Count:3 Capacity: 3

value.Clear();
//此时 Count:0 Capacity: 3
value.TrimExcess();
//此时 Count:0 Capacity: 0