Hello all I new in silverlight And i found one strange thing..

when i tried to bind List of object to datagrid all works fine. Values shows fine... But, when i try to use linq to select only one value. Datagrid return blanks rows..

but what is strange. where i try to get value of selected row it gives me right value...
here is code

Code:
private void LayoutRoot_Loaded(object sender, RoutedEventArgs
...