asp.net| Dynamic | pagination | load | Controls dynamically load asp.net paging controls
Zhengzo 2004-11-30
It is simpler to load controls dynamically in the ASP.net, where I'm talking about loading the user control, which is typically loaded with a postback event in the user control, which needs to keep the new data back.
First to build the paging user control, because the previous articles are talking about these things, so directly to the change, pagination code can view the above article 1, article 2, the following is a part of the user control code.
public class PagingControl:System.Web.UI.UserControl
{
private int PageCount;
private int recordCount;
......
private void Page_Load (object sender, System.EventArgs e)
{
if (! Page.IsPostBack)
{
Datagriddatabind ();
}
}
Binding Data
private void Datagriddatabind ()
{
DataSet ds = Getcustomersdata (pageindex,pagesize,ref recordcount,ref PageCount);
This. Datagrid1.virtualitemcount = RecordCount;
This. DataGrid1.DataSource = ds;
This. Datagrid1.databind ();
Setpagingstate ();
}
Bind a new page
private void Lbtnnavigation_click (object sender, System.EventArgs e)
{
LinkButton btn = (LinkButton) sender;
Switch (btn.commandname)
{
Case "a":
PageIndex = 0;
Break
Case "Prev":
PageIndex = PageIndex-1;
Break
Case "Next":
PageIndex = PageIndex + 1;
Break
Case "Last":
PageIndex = PageCount-1;
Break
}
Datagriddatabind ();
}
......
}
On top we noticed that in the page load event, we judged if (! Page.IsPostBack) to prevent two binding when the postback is loaded, because the first time is completely unnecessary and ultimately is determined by the binding in Lbtnnavigation_click.
Assuming that Pagingcontrol.ascx is the file name of the user control above, and that the page file is in the same directory as the page, the following is the code for the aspnetcommonpaging.aspx file, and in order to load dynamically, a placeholder control is placed on the pages to load the previous user control.
The front desk documents are as follows:
<%@ Page language= "C #" codebehind= "AspnetCommonPaging.aspx.cs" autoeventwireup= "false" inherits= " Aspnetpaging.aspnetcommonpaging "%>
<! DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 transitional//en" >
<HTML>
<HEAD>
<title>AspnetCommonPaging</title>
</HEAD>
<body>
<form id= "Form1" method= "POST" runat= "Server" >
<asp:placeholder id= "PlaceHolder1" runat= "Server" ></asp:PlaceHolder>
</form>
</body>
</HTML>
Background code files are also relatively simple:
Namespace Aspnetpaging
{
public class AspnetCommonPaging:System.Web.UI.Page
{
protected System.Web.UI.WebControls.PlaceHolder PlaceHolder1;
private void Page_Load (object sender, System.EventArgs e)
{
PLACEHOLDER1.CONTROLS.ADD (Page.LoadControl ("~/pagingcontrol.ascx"));
}
Code generated #region the Web forms Designer
Override protected void OnInit (EventArgs e)
{
InitializeComponent ();
Base. OnInit (e);
}
<summary>
Designer supports required methods-do not use the Code editor to modify
The contents of this method.
</summary>
private void InitializeComponent ()
{
This. Load + = new System.EventHandler (this. Page_Load);
}
#endregion
}
}
The PlaceHolder1.Controls.Add (Page.LoadControl ("~/pagingcontrol.ascx")) is where the Pagingcontrol user control is loaded onto the current page. If you do not want to use placeholder, we can also use other container controls, just add to the Controls collection.
Note that if you do this in this way, it will not be loaded when the page is back, and then the paging event will not be triggered.
private void Page_Load (object sender, System.EventArgs e)
{
if (! Page.IsPostBack)
PLACEHOLDER1.CONTROLS.ADD (Page.LoadControl ("~/pagingcontrol.ascx"));
}
Now let's look at the order in which the main events are executed: Set breakpoints, and get the following order.
First: Page oninit event--> page Page_Load event à control oninit event à control Page_Load event.
Paging Postback: Page OnInit Event--> page Page_Load event à control oninit event à control Page_Load event Àlbtnnavigation_click paging event.
If we put the page load code on the page OnInit event:
Override protected void OnInit (EventArgs e)
{
InitializeComponent ();
PLACEHOLDER1.CONTROLS.ADD (Page.LoadControl ("~/pagingcontrol.ascx"));
Base. OnInit (e);
}
So what is the order of events to be executed?
First time: Page OnInit event--> control oninit Event à page Page_Load event à control Page_Load event.
Paging Postback: Page OnInit event--> control oninit Event à page Page_Load event à control Page_Load event Àlbtnnavigation_click paging event.
I think it is important to understand the sequence of events in order to interoperate with multiple controls, and also to help the optimizer improve performance.
