title: Sorting ObservableCollection
body: <p>Suppose I have <code>ObservableCollection</code> of employee class </p>
  
  <pre><code>public ObservableCollection&lt;Employee&gt; employeeCollection = new ObservableCollection&lt;Employee&gt;();
  
  public class Employee
  {
      public string FirstName { get; set; }
      public string LastName { get; set; }
      public double MobileNumber { get; set; }
      public string City { get; set; }
      public int Age { get; set; }
  
      public Employee() {}
  }
  </code></pre>
  
  <p>now I am trying to sort the <code>ObservableCollection</code> (“employeeCollection”) 
  by appropriate selection by user from combobox[it will be….Sort By FirstName….Sort By MobileNumber etc…]..</p>
  
  <p>and it is required to <strong>get back sorted observable collection….</strong>
  Means it <strong>should not be in form of “var” it should be 
  <code>ObservableCollection&lt;Employee&gt;</code></strong> </p>
  
  <p>So I can assign back it to <code>“ItemsSource”</code> property of <code>“ItemsControl”</code>…</p>
  
  <p>Thanks……</p>