c# 反向排序字串的方法 ( 不使用Array.Sort )

   private void button1_Click(object sender, EventArgs e)
        {
            string input = this.textBox1.Text;
            string output = "";
            string[] lala= new string[input.Length];
            for (int i = 0; i < input.Length; i++)
            {
                lala[input.Length-i-1]=input.Substring(i,1);
            }
            for (int j = 0; j < input.Length; j++)
            {
                output += lala[j].ToString();
            }
            this.textBox2.Text = output;
        }