Asp.net c# gridview - how to know which cell clicked
I have a gridview which has 2 header rows as below|...Name...|..............Subject1....... |...........Subject2..............|
|....................|...Theory....|.....Viva...|......Theory....|....Viva....|
|----------|-----------|---------|------------|---------|
|...John.......|......................|..................|........................|..................|
|...Ann........|......................|..................|........................|..................|
When user clicks on a cell I want to know whether he has clicked on theory or viva column.
By using gvStudent.DataKeys[row.RowIndex].Value.ToString(); I am able to retrieve the student ID which I have set as datakey for the gridview. Hence able to identify which row he clicked.
By using gvStudent.HeaderRow.Cells[index].Text; I am able to identify which Subject he clicked.
But how to know whether he has clicked on Theory or Viva column.
Any help would be appreciated.