Composite Control Losing events.

[Ashish]

HI all,
I have been battling with this problem with some time now, now iam out
of ideas what to do
basically iam planning a tab control in which page developers can define
tab abd tabelements on the page, and i can render a table with one row
being link buttons and second row with tabelements..

tha markup of the control looks like

<uc:TabStrip ID="tbMatrixProduct" runat="server">
<uc:TabElement ID="teGeneral" runat="server" Description="General">
<uc:GeneralProduct ID="GeneralProduct1" runat="server" />

</uc:TabElement>
<uc:TabElement ID="teDescription" runat="server"
Description="Description">
<ucroductDescription ID="ProductDescription1" runat="server" />
</uc:TabElement>
</uc:TabStrip>

i have two controls with tabcontrol having ParseChildren Attribute, and
having a ControlBuilder defined for TabElement.

The RenderChildControl method looks like


protected override void CreateChildControls()
{

Controls.Clear();
Table cTable = new Table();
cTable.ID = "tbl" + this.ID;

cTable.Rows.Add(new TableRow());
//create link button row and add a link button for each tab
double width = Math.Floor((double)100 / (Elements.Count+1));

foreach(TabElement element in mElements)
{
//create link buttons here
}

TableCell panelcell = new TableCell();
panelcell.ColumnSpan = mElements.Count +1 ;
panelcell.Width = new Unit( "100%");

// create tabelements controls here
foreach (TabElement element in mElements)
{
Panel holder = new Panel();
holder.ID = "pnl" + element.ID;
holder.Controls.Add(element);
holder.Visible = (VisibleTabId == element.ID);
panelcell.Controls.Add(holder);
}


so far so good, everything comes up just fine, but one of the
usercontrols in tabelements is having nested datalist..., thats where
thr trouble begins...

the child datalist is having link buttons, and their event handlers
never get called ...

I can put the user control on the page and it works fine, but when i put
it on my TabControl, it stops firing events...

I have tried wiring up events on the markup, in the code behind
everywhere, but the events dont get called.


I can confirm that the usercontrol is not loading the entire datalists
on the post back, but i dont know why, and how can i make it..., i can
post the whole code if someone is interested in looking at the problem...

thanks

 

[recoil]

Ashish. The most common reason for this problem is usually because you're not
adding the child control's to the Control's early enough.
Your child controls and any controls for that matter need to be a part of
the whole Page hiearchy no later then Onload (generally speaking). You can go
later, but the later you go the more prone to problems you are.

So you should go through hopefully with a debugger and make sure all of your
controls are part of the hierarchy by the time OnLoad triggers. You should
also make sure that all of these controls have a specified ID and that this
ID is the same upon postback. Also double verify that the events are being
attached and the appropriate __doPostBack is being generated.

Another thing that your Control should do is implement the methodless
Interface INamingContainer. This ensures that your control has a
NamingContainer example $ctl00$Mycontrol$lnkChild and can also solve lots of
similar problems.

Hope this helps.

 

[Ashish]

hi there,
thanks for your interest in this problem,

after a couple of days of search and frustation, i found out following
things, please let me know if you see anything wrong in them

1. CreateChildControls at OnLoad ( some postbacks started to fire after
this)

2. CreateChildControls again at PreRender -- this is because new
databindings might create new child controls ( again more improvements
after i did this)

3. Iam using CompositeControl which i think should take care of the
NamingContainer issue.

4. The control in which Gridview is embedded in a datalist works fine
now, with all events firing as expected, but the control in which
datalist is embedded in a datalist is the child datalist's events dont
fire !

Would appreciate if you could give any other pointers

thanks

 

[recoil]

I suggest putting a INamingContainer on it "just" in case. It's a painless
method just tack on a , INamingContainer and recompile and etc. It doesn't
have any other code that you have to implement.

The second thing to do is to put a break point on the Control's Load and
when you click a link take a look at the Request.Form variables there are 2
or 3 keys that you want to look at . Pay careful attention to the key that
specifies what control invoked the event. Then go find that control and find
out what it's UniqueID / ClientID is. Also double check, is that control's
event getting bound before or after?