C# da While ile Atama

c#

private void button1_Click(object sender, EventArgs e)

        {

            int n, a = 1;

            string b = "1";

            n = Convert.ToInt32(textBox1.Text);

            while (n>=a)

            {

                listBox1.Items.Add(b);

                a++;

                b = b + a;

            }

        }