title: Get primary key value of selected row item in DataGrid using WPF
body: <p>I have a <code>DataGrid</code>, bound to database table <code>customer</code>. </p>
  
  <p>I need to select the primary key <code>ID</code> value from database table of selected row in DataGrid.</p>
  
  <p>How to do it ? please Help ..</p>