title: How to call method when Collection has given count of items
body: <p>I would like to invoke a method when into my List property were added specific count of items. Actually I need to find way how to automatically check if a Collection has given count of items and after that call a method.</p>
  
  <p>Ok, one example. I have a class MyClass</p>
  
  <pre><code>public class MyClass
  {
      public List&lt;string&gt; Url { get; set; }
  
      public void fullList()
      {
          //some work with the List
      }
  }
  </code></pre>
  
  <p>And now somewhere in main function I create instance of MyClass and add some items.</p>
  
  <pre><code>MyClass mc = new MyClass();
  mc.Url = new List&lt;string&gt;();
  mc.Url.Add("www.1.com");
  mc.Url.Add("www.2.com");
  //now on 3rd added item I want to invoke method fullList from class MyClass
  mc.Url.Add("www.3.com");
  </code></pre>