一个自定义控件的click事件不响应

    protected void lbn_Click(Object sender, EventArgs e)
    {
        Response.Write("asd");
    }    private int totalNum;
    private int cellNum;
    public int CellNum
    {
        set { cellNum = value; }
        get { return cellNum; }
    }
    public int TotalNum
    {
        set { totalNum = value; }
        get { return totalNum; }
    }
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            Initial();
        }
    }
    public void Initial()
    {
        int num = 0;
        int rowNum = (int)(totalNum / cellNum) + 1;
        for (int i = 1; i <= rowNum; i++)//i控制行
        {
            TableRow tr = new TableRow();
            for (int j = 1; j <= cellNum; j++)//j控制列 列数由用户定义
            {
                if (num < totalNum)
                {
                    num++;
                    TableCell tc = new TableCell();
                    tc.BackColor = Color.Gray;
                    tc.Width = 150;
                    tr.Controls.Add(tc);
                    LinkButton lb = new LinkButton();
                    lb.ID = num.ToString();
                    ViewState[lb.ID] = true;
                    lb.Text = "<center>第" + num + "题</center>";
                    lb.ForeColor = Color.White;
                    lb.Font.Size = 12;
                    lb.Click += new EventHandler(lbn_Click);
                    CheckBox cb = new CheckBox();
                    cb.ID = num.ToString();
                    cb.Text = "<right>我有疑惑</right>";
                    cb.Font.Size =7;
                    tc.Controls.Add(lb);
                    tc.Controls.Add(cb);
                }
            }
            QuestionTable.Rows.Add(tr);
        }
    }
调试时点击linkbutton后只是页面刷新了下，不响应事件
求解决方案