ICallbackHandler实现GridView无刷新实时更新

  GridView的数据显示一般是固定的,假如要像Ajax那样实现GridView数据动态更新而不刷新页面,就有些难度了.客户提出的需求,没办法,也得去试着想办法实现.
  涉及到Asp.Net事件机制的实现"_doPostback".Asp.Net的底层封装了XMLHttpRequest异步请求对象.在WebResource.axd中可以查看到这些封装的JavaScript.对于页面的异步请求,我们需要实现ICallbackEventHandler接口,并显示实现其中的GetCallbackResult()和RaiseCallbackEvent()这两个方法.废话不多少,假如了解Asp.Net机制的话一看就明白了.代码就贴在下面:

public   partial   class  upload_MixInfo : System.Web.UI.Page,System.Web.UI.ICallbackEventHandler
{
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            GetAllUser();
        }
        string cbReference = Page.ClientScript.GetCallbackEventReference(Page, "", "Refresh", "");
        btnGet.Attributes.Add("onclick",cbReference);
        string script="";
        script+="<script>\r\n";
        script+="function Refresh(DataFromServer){\r\n";
        script+="document.getElementById('Result').innerHTML=DataFromServer;\r\n";
        script+="}\r\n</script>\r\n";
        Page.ClientScript.RegisterClientScriptBlock(this.GetType(), "Refresh", script);
    }
    public string GetCallbackResult()
    {
        return RenderControl(Test);
    }
    public void RaiseCallbackEvent(string eventArgument)
    {
        GetAllUser();
    }
    private string RenderControl(Control c)
    {
        StringWriter writer1 = new StringWriter(CultureInfo.InvariantCulture);
        HtmlTextWriter writer = new HtmlTextWriter(writer1);
        c.RenderControl(writer);
        writer.Flush();
        writer.Close();
        return writer1.ToString();
    }
    protected void GetAllUser()
    {
        string sql = @"(Transform Sum(Nums)
select [Users].[UserName] as 地区负责人 from (([Users] left join [User_Type] on [Users].UserId=[User_Type].UserId)  left join [Type] on [User_Type].TypeId=[Type].TypeId)  GROUP BY [Users].UserName
PIVOT [Type].TypeId)";
        OleDbConnection con = DBConn.NewConnection();
        OleDbCommand cmd = new OleDbCommand(sql, con);
        OleDbDataAdapter adapter = new OleDbDataAdapter(cmd);
        DataTable dt=new DataTable();
        adapter.Fill(dt);
        dt.Columns.Remove(dt.Columns[1]);
        sql = "select * from [Type]";
        cmd.CommandText = sql;
        DataTable t = new DataTable();
        adapter=new OleDbDataAdapter(cmd);
        adapter.Fill(t);
        DBConn.ResourceDispose(cmd);
        for (int i = 0; i < t.Rows.Count; i++)
        {
            for (int j = 0; j < dt.Columns.Count; j++)
            {
                if (t.Rows[i]["TypeId"].ToString() == ((DataColumn)dt.Columns[j]).ColumnName)
                {
                    dt.Columns[j].ColumnName = t.Rows[i]["TypeName"].ToString();
                }
            }
        }
        Test.DataSource = dt;
        Test.DataBind();
    }
}

< body >
     < form  id ="form1"  runat ="server" >
     < input  type ="button"  runat ="server"  id ="btnGet"  value ="Get"  style ="display:none" />
     < div  id ="Result" >
         < asp:GridView  ID ="Test"  runat ="server"  CellPadding ="4"  ForeColor ="#333333" >
             < FooterStyle  BackColor ="#507CD1"  Font-Bold ="True"  ForeColor ="White"   />
             < RowStyle  BackColor ="#EFF3FB"   />
             < PagerStyle  BackColor ="#2461BF"  ForeColor ="White"  HorizontalAlign ="Center"   />
             < SelectedRowStyle  BackColor ="#D1DDF1"  Font-Bold ="True"  ForeColor ="#333333"   />
             < HeaderStyle  BackColor ="#507CD1"  Font-Bold ="True"  ForeColor ="White"   />
             < EditRowStyle  BackColor ="#2461BF"   />
             < AlternatingRowStyle  BackColor ="White"   />
         </ asp:GridView >
     </ div >
     </ form >
     < script  type ="text/javascript" > function btnclick(){document.getElementById("btnGet").click();}setInterval("btnclick()",10000); </ script >
</ body >