以编程方式添加用户控件内一个UpdatePanel [英] Programmatically Adding User Controls Inside An UpdatePanel
问题描述
我无法动态地添加与部分回发更新面板内部控制。我读过关于动态控件很多文章，我知道如何添加和回传维护他们但大部分信息不适，不会对部分回发工作。我无法找到有关添加和使用的UpdatePanel维护它们任何有用的信息。我想做到这一点，而无需创建一个Web服务，如果可能的。没有任何人有任何意见或引用一些有用的信息？
I'm having trouble dynamically adding controls inside an update panel with partial postbacks. I've read many articles on dynamic controls and I understand how to add and maintain them with postbacks but most of that information doesn't apply and won't work for partial postbacks. I can't find any useful information about adding and maintaining them with UpdatePanels. I'd like to do this without creating a web service if it's possible. Does anyone have any ideas or references to some helpful information?
推荐答案
这是，我认为，对于asp.net程序员的常见问题之一，但实际上并不是那么难得到它的权利，当你知道是怎么回事在（永远记住您的视图状态！）。
This is, I think, one of the common pitfalls for asp.net programmers but isn't actually that hard to get it right when you know what is going on (always remember your viewstate!).
以下code的一件事情解释如何完成的。这是一个简单的页面，用户可以点击，这将触发一个动作，将用户控件添加到页面中的UpdatePanel内的菜单上。
（这code是借<一个href=\"http://geekswithblogs.net/rashid/archive/2007/08/11/Loading-UserControl-Dynamically-in-UpdatePanel.aspx\">from这里，并有其它更多的关于这个主题）的信息
the following piece of code explains how things can be done. It's a simple page where a user can click on a menu which will trigger an action that will add a user control to the page inside the updatepanel.
(This code is borrowed from here, and has lots more of information concerning this topic)
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="SampleMenu1.aspx.cs" Inherits="SampleMenuPage1" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>Sample Menu</title>
</head>
<body>
<form id="form1" runat="server">
<asp:Menu ID="Menu1" runat="server" OnMenuItemClick="Menu1_MenuItemClick">
<Items>
<asp:MenuItem Text="File">
<asp:MenuItem Text="Load Control1"></asp:MenuItem>
<asp:MenuItem Text="Load Control2"></asp:MenuItem>
<asp:MenuItem Text="Load Control3"></asp:MenuItem>
</asp:MenuItem>
</Items>
</asp:Menu>
<br />
<br />
<asp:ScriptManager ID="ScriptManager1" runat="server"></asp:ScriptManager>
<asp:UpdatePanel ID="UpdatePanel1" runat="server" UpdateMode="Conditional">
<ContentTemplate>
<asp:PlaceHolder ID="PlaceHolder1" runat="server"></asp:PlaceHolder>
</ContentTemplate>
<Triggers>
<asp:AsyncPostBackTrigger ControlID="Menu1" />
</Triggers>
</asp:UpdatePanel>
</form>
</body>
</html>
和
using System;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
public partial class PlainSampleMenuPage : System.Web.UI.Page
{
private const string BASE_PATH = "~/DynamicControlLoading/";
private string LastLoadedControl
{
get
{
return ViewState["LastLoaded"] as string;
}
set
{
ViewState["LastLoaded"] = value;
}
}
private void LoadUserControl()
{
string controlPath = LastLoadedControl;
if (!string.IsNullOrEmpty(controlPath))
{
PlaceHolder1.Controls.Clear();
UserControl uc = (UserControl)LoadControl(controlPath);
PlaceHolder1.Controls.Add(uc);
}
}
protected void Page_Load(object sender, EventArgs e)
{
LoadUserControl();
}
protected void Menu1_MenuItemClick(object sender, MenuEventArgs e)
{
MenuItem menu = e.Item;
string controlPath = string.Empty;
switch (menu.Text)
{
case "Load Control2":
controlPath = BASE_PATH + "SampleControl2.ascx";
break;
case "Load Control3":
controlPath = BASE_PATH + "SampleControl3.ascx";
break;
default:
controlPath = BASE_PATH + "SampleControl1.ascx";
break;
}
LastLoadedControl = controlPath;
LoadUserControl();
}
}
为code的后面。
for the code behind.
这基本上它。你可以清楚地看到，视图状态被保持着的 LastLoadedControl 的而控件本身是动态添加到页面（在UpdatePanel内（实际上是UpdatePanel内占位符之内），用户点击时的菜单项，将发送异步回发到服务器。
That's basically it. You can clearly see that the viewstate is being kept with LastLoadedControl while the controls themselves are dynamically added to the page (inside the updatePanel (actually inside the placeHolder inside the updatePanel) when the user clicks on a menu item, which will send an asynchronous postback to the server.
更多信息也可以在这里找到：
More information can also be found here:
- http://aspnet.4guysfromrolla.com/articles/081402-1.aspx
- http://aspnet.4guysfromrolla.com/articles/082102-1.aspx
和<一门课程href=\"http://geekswithblogs.net/rashid/archive/2007/08/11/Loading-UserControl-Dynamically-in-UpdatePanel.aspx\">the网站保存的例子code 我在这里使用。
这篇关于以编程方式添加用户控件内一个UpdatePanel的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
