请教一个换行问题

  protected void Button1_Click(object sender, EventArgs e)
    {
        Application.Lock();
        Application["show"] =TextBox1.Text +"<br>" + Application["show"];
        Application.UnLock();
        TextBox1.Text = "";
}

public partial class show : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        if (Application["show"] == null)
        {
           ShowMessage.Text = "hello";
            Application.Lock();
            Application["show"] = "hello";
            Application.UnLock();
        }
       ShowMessage.Text = Application["show"].ToString();
    }
}
代码如上
  如果输入两行字如“很多”和“更好”，显示的是“很多<br>更好”，这不是我想要的结果，怎样让他换行成：
“很多”
“更好”