private DataGridViewCell clickedCell;

   private void dataGridView1_MouseDown(object sender, MouseEventArgs e)
   {
// If the user right-clicks a cell, store it for use by the shortcut menu.
       if (e.Button == MouseButtons.Right)
       {
           DataGridView.HitTestInfo hit = dataGridView1.HitTest(e.X, e.Y);
           if (hit.Type == DataGridViewHitTestType.Cell)
           {
               clickedCell =
                   dataGridView1.Rows[hit.RowIndex].Cells[hit.ColumnIndex];
           }
       }
   }