private void btnModificar_Click(object sender, EventArgs e)
 {
     using (var form = new IntNotaAlumno())
     {
         if (form.ShowDialog() == System.Windows.Forms.DialogResult.OK)
         {
             MessageBox.Show("Ok");
         }
         else
         {
             MessageBox.Show("Cancel");
         }
     }
 }
        private void dgvAlumnos_DoubleClick(object sender, EventArgs e)
        {
            int indice = this.dgvAlumnos.CurrentRow.Index;

            MessageBox.Show(indice.ToString());

            IntNotaAlumno formNotaAlumno = new IntNotaAlumno();
            formNotaAlumno.ShowDialog();
            //formNotaAlumno = new IntNotaAlumno (dgvAlumnos.CurrentRow.Cells[0] + dgvAlumnos.CurrentRow.Cells[1],

            //this.dgvAlumnos.CurrentRow.Index
        }