为什么ImageButton不能处发DataList中的ItemCommand事件

以下是数据绑定代码：
 protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            db.Connection();
            if (Session["user"] != null)
            {
                login1.PanelLoginVisible = false;
                login1.PanelShowInfoVisible = true;
            }
            else
            {
                login1.PanelLoginVisible = true;
                login1.PanelShowInfoVisible = false;
            }
            if (Request.QueryString["Id"] != null)
            {
                panelTj.Visible = true;
                int typeId = int.Parse(Request.QueryString["Id"].ToString());
                dataListLbTj.DataSource = db.QueryProductByTypeId(typeId, 4);
                dataListLbTj.DataBind();

                dataListLb.DataSource = db.QueryProductByTypeId(typeId, 16);
                dataListLb.DataBind();
            }
            else
            {
                panelTj.Visible = false;
                dataListLb.DataSource = db.QueryAllProduct(16);//.QueryProductByTypeId(1, 16);
                dataListLb.DataBind();
            }
            
            
            search.TextBox1Height = 20;
            search.TextBox1Width = 150;
            search.TextBox2Height = 20;
            search.TextBox3Height = 20;
            login1.UserNameHeight = 20;
            login1.PasswordHeight = 20;
            db.CloseDataBase();
        }
    }

怎么点ImageButton按钮他也不处发DataList的ItemCommand事件 --------------------编程问答--------------------
 没搞懂..
--------------------编程问答-------------------- 没看懂，帮你顶个

补充：.NET技术 ,  ASP.NET