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Bubbling up Methods in Composite Controls
Posted by David on May 9, 2008
A while back, I wrote a couple of articles (here and here) regarding encapsulating the ModalPopupExtender into a spiffy little template control that you could toss onto a page. It’s worked GREAT over the past few months, however, I hit a snag today.
I needed to call the base ModalPopupExtender’s .Show() method from code behind; however, I hadn’t bubbled that up to the Composite Control.
At first, I expected to simply add a private instance of the MPE (which is assigned to when the control is built) and then add a method to my composite control that calls the .Show() method.
private ModalPopupExtender _control;
public void Show()
{
_control.Show();
}
That sounds good, but it never fired and the _control field was always null (even though I could step through and it was assigned).
What it needed was a little reminder—a reminder to EnsureChildControls existed before trying to call Show(). Now, a quick update to the code:
public void Show()
{
this.EnsureChildControls();
_control.Show();
}
Now I can call the Show() method of the Composite Control and it works like a charm! Here’s an example (for what I’m working with at the moment) of dynamically iterating through an IDictionary and returning the values in a Modal Popup.
ASPX:
<tiredstudent:ModalPopupTemplate HeaderText=”ERC” runat=”server”
ID=”PopupDialogBox” DefaultStyle=”YUI” TargetControlId=”fakeButton” />
<asp:Button ID=”fakeButton” runat=”server” style=”display: none” />
Code-behind:
foreach (var entry in results)
{
sb.AppendLine(string.Format(“<p>{0} – {1}</p>”,
entry.Key, entry.Value));
}
PopupDialogBox.BodyText = sb.ToString();
PopupDialogBox.Show();
Will Asrari said
If I had $1 for every time EnsureChildControls() solved a problem I’d be doing pretty well.
David said
My joke to myself was the irony that I’m creating a composite control which, by definition, is an grouping of child controls and that I had to EXPLICITLY tell it to ensure they exist.
Go go .Net.