C#

public class A
{
    [Serializable]
    public class B
    {
        public int Number;
    }
}

<br />
            List<int> list = new List<int>();<br />
            list.Add(1);<br />
<br />
            IEnumerator enumerator = list.GetEnumerator();<br />
<br />
            enumerator.Reset(); // It' ok to reset the enumerator<br />
<br />
            list.Add(2);  // The collection is modified.<br />
<br />
            enumerator.Reset(); // Now InvalidOperationException is raised<br />

<br />
    class MyEnumerator:IEnumerator{<br />
        int[] integers;<br />
        <br />
        /// <br />
        /// Methods <br />
        /// <br />
<br />
        public void Reset(){ }<br />
    }