Clear all array list data
<p>Why doesn't the code below clear all array list data?</p>

<pre><code>        Console.WriteLine("Before cleaning:" + Convert.ToString(ID.Count));
        //ID.Count = 20
        for (int i = 0; i &lt; ID.Count; i++)
        {
            ID.RemoveAt(i);
        }
        Console.WriteLine("After cleaning:" + Convert.ToString(ID.Count));
        //ID.Count = 10
</code></pre>

<p>Why is 10 printed to the screen?</p>

<p>Maybe there is another special function, which deletes everything? </p>
