Как запретить ввод собственного значения в ComboBox?

comboBox1.DropDownStyle = System.Windows.Forms.ComboBoxStyle.DropDownList;

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
 
namespace WindowsFormsApplication9
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
            comboBox1.KeyPress += (sender, e) => e.Handled = true;
        }
    }
}

comboBox1.DropDownStyle = System.Windows.Forms.ComboBoxStyle.DropDownList;

comboBox1.DropDownStyle = System.Windows.Forms.ComboBoxStyle.DropDownList;

    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
            comboBox1.KeyPress += OnKeyPress;
        }
 
        void OnKeyPress(object sender, KeyPressEventArgs e)
        {
           e.Handled = true;
        }
    }

    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
            comboBox1.KeyPress += new KeyPressEventHandler(OnKeyPress);
        }
 
        void OnKeyPress(object sender, KeyPressEventArgs e)
        {
           e.Handled = true;
        }
    }