Question

我搜索并尝试过很多东西，但是我无法使用以下代码。似乎当我在c＃中有三个按钮时，如果我点击第一个按钮它会正确触发。但是，当我单击第二个按钮时，它无法加载第三个按钮。回到第一个。由于某些原因，事件似乎没有超过第一级。提前感谢您的帮助。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Diagnostics;

public partial class testingSandbox : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
    boot();
}
public void boot()
{
    firstFunc();
}
public void firstFunc()
{
    Debug.WriteLine("func1");
    Button btn1 = new Button();
    btn1.Text = "btn1";
    btn1.ID = "btn1";
    btn1.Click += new EventHandler(secFunc);
    form1.Controls.Add(btn1);
}

public void secFunc(object sender, EventArgs e)
{
    Debug.WriteLine("func2");
    Button btn2 = new Button();
    btn2.Text = "btn2";
    btn2.ID = "b2";
    btn2.Click += new EventHandler(thirdFunc);
    form1.Controls.Add(btn2);
    Button btn1 = (Button)this.FindControl("btn1");
    //btn1.Click-=new EventHandler(secFunc);
}

public void thirdFunc(object sender, EventArgs e)
{
    Debug.WriteLine("func3");
    Button btn3 = new Button();
    btn3.Text = "btn3";
    btn3.ID = "b3";
    btn3.Click += new EventHandler(fourthFunc);
    form1.Controls.Add(btn3);
}

public void fourthFunc(object sender, EventArgs e)
{
    Debug.WriteLine("func4"); 
    Button btn4 = new Button();
    btn4.Text = "btn4";
    form1.Controls.Add(btn4);
}

}

Answer 1

ASP.NET在每个请求上重新创建ENTIRE控制树。您在.ascx文件中编写的内容将被转换为C＃代码文件（您可以在ASP.NET Temporary Files文件夹中找到它）来创建控件，并且该代码在每个请求上运行。但是，在您的情况下，会发生这种情况：

Request 1:
    You start out with Button1.
Request 2:
    You start out with Button1. A click event for it is received and processed.
    In the event handler you add Button2. You end up with Button1 and Button2.
Request 3:
    You start out with Button1. A click event for Button2 is received.
    Unfortunately there is no Button2, since the control tree got recreated.
    The event is ignored. You end up with just Button1.

ASP.NET webforms中的动态控件很难。您需要手动跟踪添加的控件，并在每个后续请求的开头重新创建它们。 ASP.NET不会为你记住这一点。

c＃events：第二级后没有开火

1 个答案: