第二个事件处理程序不会从按钮触发

Question

I have 2 buttons. The first button gets drawn from the code behind. The second button gets drawn when the first button is clicked. This works perfectly. When I add a event when the second button gets clicked this event won't be triggered. As you can see in the code below there is a btnTwo_click function. If I put a breakpoint on this function the program won't even break. Is there a way to trigger this event from the code behind (not using java script)?

Here is the code, I actually use this system in a table. But this simple code has the same problem in the end.

public partial class _Default : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        ImageButton btn = new ImageButton();
        btn.Command += new CommandEventHandler(btnOne_Click);
        form1.Controls.Add(btn);
    }

    void btnOne_Click(object sender, EventArgs e)
    {
        ImageButton btn = new ImageButton();
        btn.Command += new CommandEventHandler(btnTwo_Click);
        form1.Controls.Add(btn);
    }

    void btnTwo_Click(object sender, EventArgs e)
    {
        Label lblTest = new Label(); //BREAKPOINT
        form1.Controls.Add(lblTest);
    }
}

Answer 1

只需将此行移至Page_Load事件即可运行;）

btn.Command += new CommandEventHandler(btnTwo_Click);

Answer 2

You have to add the second button on the Page_Load or Page_Init method of Page life cycle:

eg

protected void Page_Load(object sender, EventArgs e)
{
    ImageButton btn = new ImageButton();
    btn.Command += btnOne_Click;
    form1.Controls.Add(btn);

    ImageButton btn2 = new ImageButton();
    btn2.Command += btnTwo_Click;
    btn2.Visible = false;
    form1.Controls.Add(btn2);
}

void btnOne_Click(object sender, EventArgs e)
{
    // Your second button 
    form1.Controls[2].Visible = true;
}

void btnTwo_Click(object sender, EventArgs e)
{
    ImageButton btn2 = (ImageButton)sender;
    // Do something
}