动态创建访问控件（c＃） [英] Accessing controls created dynamically (c#)

问题描述

在我的代码（c＃）中，我动态地创建了一些RadioButtonLists，每个都有更多的RadioButton。我把所有的控件都放到一个特定的面板上
我需要知道的是如何稍后访问这些控件，因为它们不是在.aspx文件中创建的（从工具箱拖放）？

我尝试这样：

  foreach（面板控件中的控制小孩）
 {
 Response.Write（测试1\" ）; 
 if（child.GetType（）。ToString（）。Equals（System.Web.UI.WebControls.RadioButtonList））
 {
 RadioButtonList r =（RadioButtonList）child; 
 Response.Write（test2）; 
} 
} 
  

test1和test2不显示我的页面。这意味着这个逻辑有错误。
任何建议我可以做什么？

解决方案

每次回发后，您必须重新创建控件。

ASP.NET是无状态的，即当您将页面发布回服务器时，您的动态创建的控件将不再是页面的一部分。

上周我不得不再次克服这种情况。

我做了什么？
我保存了用于在Session对象中创建控件的数据。在PageLoad方法中，我传递了相同的数据来重新创建动态控件。

我建议的是：
编写一个方法来创建动态控件。 >

在PageLoad方法检查是否是回发...

  if （Page.IsPostBack）
 {
 //在这里重新创建你的控件。 
} 
  

一个非常重要的事情：为您动态创建的控件分配唯一的ID，以便ASP .NET可以重新创建绑定现有事件处理程序的控件，恢复其ViewState等。

  myControl.ID =myId; 
  

我很难学习这个东西如何运作。一旦你学会了，你有权力在你手中。动态创建的控件开辟了一个新的可能性世界。

正如Frank所说：您可以使用is关键字来促进您的生活...

  if（child is RadioButtonList）
  

注意：
值得一提的是， ASP.NET页面生命周期概述页面，以供进一步参考。

In my code behind (c#) I dynamically created some RadioButtonLists with more RadioButtons in each of them. I put all controls to a specific Panel. What I need to know is how to access those controls later as they are not created in .aspx file (with drag and drop from toolbox)?

I tried this:

    foreach (Control child in panel.Controls)
    {
        Response.Write("test1");
        if (child.GetType().ToString().Equals("System.Web.UI.WebControls.RadioButtonList"))
        {
            RadioButtonList r = (RadioButtonList)child;
            Response.Write("test2");
        }   
    }

"test1" and "test2" dont show up in my page. That means something is wrong with this logic. Any suggestions what could I do?

解决方案

You must recreate your controls after each postback.

ASP.NET is stateless, that is, when you postback a page to the server, your dynamically created controls won't be part of the page anymore.

Last week I had to overcome this situation once more.

What did I do? I saved the data that I used to create the controls inside Session object. On PageLoad method I passed that same data to recreate the dynamic controls.

What I suggest is: Write a method to create the dynamic controls.

On PageLoad method check to see if it's a postback...

if(Page.IsPostBack)
{
   // Recreate your controls here.
}

A really important thing: assign unique IDs to your dynamically created controls so that ASP.NET can recreate the controls binding their existing event handlers, restoring their ViewState, etc.

myControl.ID = "myId";

I had a hard time to learn how this thing works. Once you learn you have power in your hands. Dynamically created controls open up a new world of possibilities.

As Frank mentioned: you can use the "is" keyword this way to facilitate your life...

if(child is RadioButtonList)

Note: it's worth to mention the ASP.NET Page Life Cycle Overview page on MSDN for further reference.

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