Dynamic created controls not firing event handlers

[simonchristieis]

I am creating a linkbutton using xml / xslt.

However, when the page renders the method attached to the event handler doesn't fire.

I parse the controls into a placeholder on page init, and can see the controls within the trace.

I am using master pages.

Any ideas ?

Thanks in advance

Simon

 

[jmeckley]

1st code is always required for debugging a problem.

I am creating a linkbutton using xml / xslt.

I'm pretty sure this won't work. xml/xslt is just text. a LinkButton is a .net object. you need to create the button in the Init event and hook up an event handler.

protected override void Init(EventArgs e)
{
   LinkButton lb = new LinkButton();
   // set lb properties
   lb.Click += new EventHandler(LinkButton_Click);
   this.Form.Controls.Add(lb);
}

void LinkButton_Click(object sender, EventArgs e)
{
   //process event here
}

note: I don't check for postback. because the control is created dynamically, I must create the control everytime

if you want to create markup via xml/xslt you'll need to have the generated button call a webservice and minipulate the gui on the client.

Jason Meckley
Programmer
Specialty Bakers, Inc.

 

[simonchristieis]

Here is the control creation text from the xslt.

<snipped>

<asp:LinkButton ID="Test{position()}" runat="server" OnClick="DynamicButtonHandler">Proof</asp:LinkButton>

The xml / xslt is parsed using:

// oWriter contains the transformed markup
Control ctrl = Page.ParseControl(oWriter.ToString());
plcResults.Controls.Add(ctrl);

The control has been created, cos I can see it in the trace

ctl00$MainContentPlaceHolder$Test1 System.Web.UI.WebControls.LinkButton 124 0 0

However, when I click the button, the click event is not fired.

Any ideas anyone ?

 

[jmeckley]

<asp:LinkButton ID="Test{position()}" runat="server" >Proof</asp:LinkButton>

LinkButton ctrl = (LinkButton)Page.ParseControl(oWriter.ToString());
ctrl.Click += new EventHandler(LinkButton_Click);
plcResults.Controls.Add(ctrl);

void LinkButton_Click(object sender, EventArgs e)
{
   //process event here
}

Jason Meckley
Programmer
Specialty Bakers, Inc.

 

[simonchristieis]

ok - fixed it, after the controls are parsed, loop through the controls and add the events handlers.

Control ctrl = Page.ParseControl(oWriter.ToString());
plcResults.Controls.Add(ctrl);

foreach (Control ctl in plcResults.Controls)
{
 for (int i = 0; i < ctl.Controls.Count; i++)
  {
   if (ctl.Controls[i] is LinkButton)
    {
     LinkButton dynButton = (LinkButton)ctl.Controls[i];
      dynButton.Click += new System.EventHandler(this.DynamicButtonHandler);
     }
   }
}

Thanks jmeckley,

I was under the impression that the event handlers should be attached to the control as the controls were added.