title: How to make silverlight datagrid editable?
body: <p>I created a simple collection of Person with name, age and sex where all three fields have getters and setters. I bound the collection to the data grid using the itemssource. I can see the data been showed up in the data grid but it does not allow me to edit any of the rows. What do I make so that it becomes editable?</p>
  
  <p>Thanks.</p>