很多自定义控件都不能正确显示
下面这页问题特多  Question.aspx.cs页面                                               
  public partial class Question : System.Web.UI.Page
{
   [u]DataClassesDataContext[/u] DC = new [u]DataClassesDataContext[/u]();显示未能找到命名空间
   
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!Page.IsPostBack)
        {
            if (string.IsNullOrEmpty([u]ClientHelper[/u].UserCode))//显示当前上下文中不存在            {
                Session["RedirectFrom"] = Request.Url;      
                Response.Redirect("NotLogin.aspx");         //     
       }

            var query = from item in DC.tb_Catalog          //            
            select new
                        {
                            Code = item.Code,
                            Name = item.Name
                        };
            ddlCatalogCode.DataSource = query;              // 
           ddlCatalogCode.DataTextField = "Name";
            ddlCatalogCode.DataValueField = "Code";
            ddlCatalogCode.DataBind();
        }
    }
    //保存提问信息
    protected void ibtnPostQuestion_Click(object sender, ImageClickEventArgs e)
    {
        if (!ValidateCode1.CheckSN(txtCheckCode.Text))          //
        {
            lblMessage.Text = "输入验证码不正确!";
            return;
        }
        if (Page.IsValid)
        {
            [u]tb_UserInfo [/u]user = DC.tb_UserInfo.FirstOrDefault(itm => =显示未能找到命名空间
ClientHelper.UserCode);
            if (txtMark.Text.Trim() != "" && user.Mark < Convert.ToInt32(txtMark.Text))
            {
                Response.Write("<Script>window.alert('用户的分数不足!')</Script>");
                return;            
            }

            [u]tb_Question [/u]question = new tb_Question();           //显示未能找到命名空间
            question.Code = ClientHelper.BuildCode();           //
            //给实体成员赋值
            question.CatalogCode = ddlCatalogCode.SelectedValue;
            question.UserCode = ClientHelper.UserCode;
            question.Title = txtTitle.Text;
            question.Text = txtText.Text;
            if (txtMark.Text.Trim() !="")
                question.Mark = Convert.ToInt32(txtMark.Text);
            question.PostDatetime = ClientHelper.ServerDate;
            question.State = 0;                                 //
            DC.tb_Question.InsertOnSubmit(question);            //

           [u]tb_Config [/u]config = DC.tb_Config.FirstOrDefault();显示未能找到命名空间

            config.UnSolved = config.UnSolved + 1;