title: How to add item to IList<T>
body: <p>I have a IList .</p>
  
  <pre><code> IList&lt;MyClass&gt; MyList
      {
          get;
          set;
      }
  </code></pre>
  
  <p>I copy a list of Myclass to this in page load</p>
  
  <pre><code>MyList=Listofmyclass;
  </code></pre>
  
  <p>I want add a new item to MyList</p>
  
  <pre><code>MyList.Add(NewItem);
  </code></pre>
  
  <p>but when i use this code i get error "<strong>Collection was of a fixed size.</strong>"</p>
  
  <p>How to add new item to IList?</p>