往DropDownList 里面 插入一個(gè)處于0位置的item，并且他的值是 0

插入后顯示如下圖所示。

我們?cè)谛侣劰芾眄?yè)面，有用到 ajax 來(lái)實(shí)現(xiàn) 刪除的 無(wú)動(dòng)態(tài)刷新，那么對(duì)于分頁(yè)和查詢，能ajax么？? 答案是可以的

?

只需要我們把所有的方法，全部都放到?

    <asp:UpdatePanel ID="
    
      UpdatePanel1
    
    " runat="
    
      server
    
    ">

            <ContentTemplate>


  

中間即可

也就是 控件中間即可實(shí)現(xiàn) ajax 的無(wú)刷新 查詢/分頁(yè)（但是如果分頁(yè)已經(jīng)設(shè)置為 url分頁(yè)，則這個(gè)ajax 無(wú)效，分頁(yè)的時(shí)候，url還是會(huì)加入page=2這類的）

?

    
      using
    
     System;


    
      using
    
     System.Collections;


    
      using
    
     System.Configuration;


    
      using
    
     System.Data;


    
      using
    
     System.Linq;


    
      using
    
     System.Web;


    
      using
    
     System.Web.Security;


    
      using
    
     System.Web.UI;


    
      using
    
     System.Web.UI.HtmlControls;


    
      using
    
     System.Web.UI.WebControls;


    
      using
    
     System.Web.UI.WebControls.WebParts;


    
      using
    
     System.Xml.Linq;


    
      using
    
     BLL;


    
      using
    
     DAL;


    
      using
    
     Model;


    
      using
    
     System.Data.SqlClient;




    
      public
    
     partial 
    
      class
    
     admin_newsmanager : System.Web.UI.Page

{

    NewsManager nm = 
    
      new
    
     NewsManager();

    
    
      protected
    
    
      void
    
     Page_Load(
    
      object
    
     sender, EventArgs e)

    {

        
    
      if
    
     (Session["
    
      admin
    
    "] != 
    
      null
    
     && Session["
    
      admin
    
    "].ToString() == "
    
      joey
    
    ")

        {

            
    
      if
    
     (!Page.IsPostBack)

            {

                





                ddlCategory.DataTextField = "
    
      name
    
    ";

                ddlCategory.DataValueField = "
    
      id
    
    ";

                ddlCategory.DataSource = 
    
      new
    
     CategoryDAO().SelectAll();

                ddlCategory.DataBind();

                
    
      //ddlCategory.Items.Insert(0, "所有分類");
    
    

                ddlCategory.Items.Insert(0, 
    
      new
    
     ListItem("
    
      所有分類
    
    ", "
    
      0
    
    "));

               

            }

            BindNews();

        }

        
    
      else
    
    

        {

            Response.Redirect("
    
      login.aspx
    
    ");

        }



    }



    
    
      /// <summary>綁定新聞列表
    
    
      /// 
    
    
      /// </summary>
    
    
      private
    
    
      void
    
     BindNews()

    {

        
    
      string
    
     key = txtKey.Text.Trim();

        
    
      int
    
     pagesize = anp.PageSize;

        
    
      int
    
     pageindex = anp.CurrentPageIndex;

        
    
      string
    
     cond = "
    
    
    ";

 

            cond = "
    
       title like '%
    
    " + key + "
    
      %'   
    
    ";

 

        
    
      string
    
     cateid = ddlCategory.SelectedValue;
    
      //默認(rèn)為0的是新聞?lì)悇e是  選擇全部
    
    
      if
    
     (cateid != "
    
      0
    
    ")  //如果不等于0 說(shuō)明選擇的類別不為空

        {

            cond +=  "
    
       and caid = 
    
    " + cateid;

        }

        anp.RecordCount = nm.CalcCount(cond);



        repNews.DataSource = nm.Select(pagesize, pageindex, cond);

        
    
      //repNews.DataSource = new NewsManager().SelectAll();
    
    

        repNews.DataBind();

    }





    
    
      protected
    
    
      void
    
     lbtnDelNews_Click(
    
      object
    
     sender, EventArgs e)

    {

        LinkButton lb = (LinkButton)sender;

        
    
      string
    
     newsid = lb.CommandArgument;



        
    
      bool
    
     b = 
    
      new
    
     NewsManager().Delete(newsid);

        
    
      if
    
     (b) 
    
      //如果刪除成功
    
    

        {

            BindNews();

        }

        
    
      else
    
    

        {

            Page.ClientScript.RegisterStartupScript(Page.GetType(), "
    
      message
    
    ", "
    
      <script language='javascript' defer>alert('刪除失敗！');</script>
    
    ");

        }



    }

    
    
      protected
    
    
      void
    
     anp_PageChanged(
    
      object
    
     sender, EventArgs e)

    {

        BindNews();

    }

    
    
      protected
    
    
      void
    
     btnSearch_Click(
    
      object
    
     sender, EventArgs e)

    {



        BindNews();

    }

}




  

牛腩新聞發(fā)布系統(tǒng) aspnetpager分頁(yè)（使用Repeater 分頁(yè),使用ajax刷新） DropDownList 插入一個(gè)item