根据下面的代码,它似乎不起作用。我可以在page_Load之后动态地向页面添加控件,但我不能将EventHandler连接到它
下面是我的代码:
public partial class AddingControlsToPanelAtRuntime : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
DrawPage();
}
private void DrawPage()
{
Label label;
label = new Label();
label.ID = "Label1";
label.Text = "Label 1";
Panel1.Controls.Add(label);
Panel1.Controls.Add(new LiteralControl("<br />"));
label = new Label();
label.ID = "Label2";
label.Text = "Label 2";
Panel1.Controls.Add(label);
Panel1.Controls.Add(new LiteralControl("<br />"));
LinkButton linkButton1 = new LinkButton();
linkButton1.ID = "linkButton1";
linkButton1.Text = "linkButton 1";
linkButton1.Click += new EventHandler(LinkButton_Click);
Panel1.Controls.Add(linkButton1);
Panel1.Controls.Add(new LiteralControl("<br />"));
LinkButton linkButton2 = new LinkButton();
linkButton2.ID = "linkButton2";
linkButton2.Text = "linkButton 2";
linkButton2.Click += new EventHandler(LinkButton_Click);
Panel1.Controls.Add(linkButton2);
}
protected void LinkButton_Click(object sender, EventArgs e)
{
Panel1.Controls.Add(new LiteralControl("<p>"));
LinkButton linkButton4 = new LinkButton();
linkButton4.ID = "linkButton4";
linkButton4.Text = "linkButton 4";
linkButton4.Click += new EventHandler(LinkButton_Click);
Panel1.Controls.Add(linkButton4);
}
}
因此,在从Page_Load调用的DrawPage()中,所有控件都很好地添加到了Panel中,EventHandlers也完美地连接在一起。
当我点击LinkButton1或LinkButton2时,它们正确地调用了LinkButton_click()。在LinkButton_Click()中,我在运行时添加了另一个控件,并连接到EventHandler,但当我点击该链接按钮时,它只发布回Page_Load,而不调用LinkButton_Colick(。
那么,基于ASP.NET管道,我在这里尝试做的事情是不可能的吗?
您想要做的事情是可能的。真正了解页面生命周期会有所帮助。http://msdn.microsoft.com/en-us/library/ms178472.aspx
以下是您页面上当前发生的事情。
Page_Load
Create Controls (label 1/2, linkbutton 1/2)
-> Browser renders label 1/2, linkbutton 1/2
-> User Clicks link button 1 or 2
Page_Load
Create Controls (label 1/2, linkbutton 1/2)
Control events fire
LinkButton_Click fires
Adds another linkbutton (linkbutton 4)
-> Browser renders label 1/2, linkbutton 1/2 AND 4
-> User Clicks link button 4
Page_Load
Create Controls (label 1/2, linkbutton 1/2)
Control events fire
(There is no link button 4 so nothing happens)
-> Browser renders label 1/2, linkbutton 1/2 (4 is missing)
您缺少的核心部分是重新添加动态创建的控件。每个控件都需要在每次发布后重新读取(如果您关心视图状态,则按照相同的顺序)。您可以通过视图状态或任何其他回发持久机制跟踪需要读取的内容。