void Temizle()
        {
            foreach (TabPage item in tabControl1.TabPages)
            {
                foreach (Control ct in item.Controls)
                {
                    if (ct is TextBox)
                    {
                        ct.Text = "";
                    }
                    if (ct is ComboBox)
                    {
                        ((ComboBox)ct).SelectedIndex = -1;
                    }
                }
            }

            foreach (int i in clbMorbi.CheckedIndices)
            {
                clbMorbi.SetItemCheckState(i, CheckState.Unchecked);
            }

            foreach (int i in clbOpTur.CheckedIndices)
            {
                clbOpTur.SetItemCheckState(i, CheckState.Unchecked);
            }

            foreach (int i in clbDrAdi.CheckedIndices)
            {
                clbDrAdi.SetItemCheckState(i, CheckState.Unchecked);
            }

            txtHastaNO.Text = _n.HastaNo();
        }