อยากให้ combobox เลือกได้จากที่เราคีย์ลง textbox (win, C#)

 private void textBox1_TextChanged(object sender, EventArgs e)
        {
            if (this.textBox1.Text != string.Empty)
            {
                try
                {
                    this.comboBox1.SelectedIndex = int.Parse(this.textBox1.Text);
                }
                catch (Exception)
                {
                    this.comboBox1.SelectedIndex = -1;
                }
            }
            else
            {
                this.comboBox1.SelectedIndex = -1;    
            }
        }

        private void ComboboxChangeValue(int value)
        {
            this.comboBox1.SelectedIndex = value;
        }