private void rbHafiza_CheckedChanged(object sender, EventArgs e)
 {
     if (rbHafiza.Checked)
     {
         dersService = new DersService(new MemoryOperations());
         FillGrid();
     }
 }
 private void rbDosya_CheckedChanged(object sender, EventArgs e)
 {
     if (rbDosya.Checked)
     {
         dersService = new DersService(new FileOperations());
         FillGrid();
     }
 }
 public Form1()
 {
     InitializeComponent();
     //dersService = new DersService(new MemoryOperations());
     dersService = new DersService(new FileOperations());
 }