creating dynamic control in asp.net

问题:

I'm creating a fileupload control on a linKbutton click event. First time it's creating the controls, but if I press the link button second time, it's not creating. What is the problem with that? The following is my code:

protected void LinkButton1_Click(object sender, EventArgs e)
{
    newattach();
}

private void newattach()
{
    int i;
    for (i = 0; i < 2; i++)
    {
        count++;
        FileUpload f1 = new FileUpload();
        f1.ID = "fileupload" + count.ToString();
        f1.Height = 34;
        f1.Width = 212;
        Panel1.Controls.Add(f1);
    }
}

and count is a static variable. Please help.

回答1:

When you create controls dynamically with ASP.NET you need to recreate the control every time you post back, generally you recreate the control on Page_Load. That is most likely the cause of your problem.