private void button3_Click(object sender, EventArgs e)
        {
            StudentDb sdb=new StudentDb();
               int result= sdb.Delete(Convert.ToInt32(sndeleteTxtBox.Text));

            if(result==-1)
            {
                MessageBox.Show("Row couldn't be deleted");
            }

            else
            {
                MessageBox.Show(result+" row deleted");
            }

            LoadListView();
        }
        public void LoadListView()
        {
            listView1.Items.Clear();
            StudentDb sdb = new StudentDb();
            List<Student> listOfStudent = sdb.SelectAll();

            foreach (Student s in listOfStudent)
            {
                ListViewItem row = new ListViewItem();
                row.Text = s.Sn.ToString();
                row.SubItems.Add(s.Name);
                row.SubItems.Add(s.Age.ToString());
                row.SubItems.Add(s.Roll.ToString());

                listView1.Items.Add(row);
            }
        }
        private void button2_Click(object sender, EventArgs e)
        {
            Student s= new Student();
            s.Name = NameTextbox.Text;
            s.Roll = Convert.ToInt32(RollTextbox.Text);
            s.Age = Convert.ToInt32(AgeTextbox.Text);
            s.Sn = Convert.ToInt32(SnTextbox.Text);

            StudentDb sdb=new StudentDb();
            int result=sdb.Update(s);

            if(result==-1)
            {
                MessageBox.Show("Couldnt be updated");
            }

            else
            {
                MessageBox.Show(result+" Row updated");
            }

            LoadListView();
        }
        private void button4_Click(object sender, EventArgs e)
        {
            Student s=new Student();
            s.Name = NameTextbox.Text;
            s.Roll = Convert.ToInt32(RollTextbox.Text);
            s.Age = Convert.ToInt32(AgeTextbox.Text);

            StudentDb sdb=new StudentDb();
            int result=sdb.Insert(s);

            if(result==-1)
            {
                MessageBox.Show("Data cannot be inserted");

            }

            else
            {
                MessageBox.Show(result +"rows inserted");
            }

            LoadListView();
        }