public Employee_View(int id, View_Strategy s)
        {
            InitializeComponent();
            strategy = s;
            DataTable dt = strategy.View_operation(id);

            dataGridView1.DataSource            = dt;
            dataGridView1.Columns[3].HeaderText = "Type";
            dataGridView1.Refresh();
        }
        private void button1_Click(object sender, EventArgs e)
        {
            DataTable dt = strategy.View_operation(Convert.ToInt32(comboBox1.SelectedValue));

            new Doctor_View(dt).Show();
        }