急!! 在用户控件中动态加载自定义控件的事件不能响应 高手给看看

我在一个用户控件中自定义加载linkbutton  并且注册了事件  但是事件不能响应  如果相同的代码写在别的页面就好使  不解  
代码如下::
   for (int i = 1; i <= totalPage; i++)
        {
            ddlSelectpage.Items.Add("第"+i.ToString()+"页");
            LinkButton link = new LinkButton();
            link.Text = i.ToString();
            link.CssClass = "linkbutton";
            link.Click += new EventHandler(link_Click);
            Label4.Controls.Add(link);
            
        }

   void link_Click(object sender, EventArgs e)///函数中的代码不要紧 关键是现在程序不能进入此函数
    {
        currentNumber = Convert.ToInt32((sender as LinkButton).Text.ToString());
        if (DeparmentID != -1)
        {
            DataList1.DataSource = GetProductList.getPrductlistByDepartmentID(DeparmentID, currentNumber, MaximumRows, DescriptionLength, out  pageNumber, out totalPage);
        }
        else
            if (CategoryID != 0)
            {
                DataList1.DataSource = GetProductList.getPrductlistByCategoryID(CategoryID, currentNumber, MaximumRows, DescriptionLength, out  pageNumber, out totalPage);
            }
            else
            {
                DataList1.DataSource = GetProductList.getProductList(currentNumber, maximumRows, out  pageNumber, out totalPage);

            }

        DataList1.DataBind();
        Checkbutton();
    }
   


 protected void ProductBindByDepartmentID()
    {
        currentNumber = Convert.ToInt32(WebConfigurationManager.AppSettings["currentNumber"].ToString());
        //maximumRows = Convert.ToInt32(WebConfigurationManager.AppSettings["MaximumRows"].ToString());
        DescriptionLength = Convert.ToInt32(WebConfigurationManager.AppSettings["DescriptionLength"].ToString());
        DataList1.DataSource = GetProductList.getPrductlistByDepartmentID(DeparmentID, currentNumber, MaximumRows, DescriptionLength, out  pageNumber, out totalPage);
        DataList1.DataBind();
        for (int i = 1; i <= totalPage; i++)
        {
            ddlSelectpage.Items.Add("第" + i.ToString() + "页");
        }
        ddlSelectpage.SelectedIndex = currentNumber - 1;
    }