title: Method to find DataGrid Row is selected or not?
body: <p>I am new to C# and WPF. Issue I have is on datagrid I am displaying datatable data. I need to update data based on selected row. I am able to achieve that. </p>
  
  <p>However, when I do not select any row on datagrid it does select default row as '0' and I do not want that I want result as -1 or error because I have not selected any row there?</p>