C# da Belli Aralıklarda Sayı Atama

c#

  private void button1_Click(object sender, EventArgs e)

        {

            int a, b;

            a = Convert.ToInt32(textBox1.Text);

            b = Convert.ToInt32(textBox2.Text);

            if (a<=b)

            {

                for (int i = a; i <=b; i++)

                {

                    listBox1.Items.Add(i);

                }

            }

            else

            {

                for (int i = a; i >= b; i--)

                {

                    listBox1.Items.Add(i);

                }

            }

        }