title: FindIndex on list by linq
body: <p>How may i get index using linq ? I want to find by FieldNo and get back to index. let say if i search 2 it should be return index 1.</p>
  
  <p><img src="https://i.stack.imgur.com/UI68q.png" alt="enter image description here"></p>
  
  <p>Regards,</p>