private void Button2_Click(object sender, System.EventArgs e)
  {
   string[] a=new string[2];
   a[0]="aa";
   a[1]="bb";
   Application.Add("a",a);//将值赋给 Application["a"]
  }

  private void Button3_Click(object sender, System.EventArgs e)
  {
   this.ListBox1.Items.Clear();//清除列表里的值
   string[] b=(string[])Application["a"];//将值赋给数组 b
    for (int i=0;i<b.Length;i++)
    {
    this.ListBox1.Items.Add(b[i]);
    }
  }