private void dataGridView1_CellClick(object sender, DataGridViewCellEventArgs e)
 {
     if (e.ColumnIndex == 11)
     {
         yonetim.OgrenciSil(dataGridView1.CurrentRow.Cells[3].Value.ToString());
         MessageBox.Show("Silinen Kullanıcı : " + dataGridView1.CurrentRow.Cells[2].Value.ToString(), "Butondan Detay");
         new DataGridDoldur().DataGridSilinmisOgrenci(dataGridView2);
         new DataGridDoldur().DataGrid(dataGridView1);
     }
 }