Not answered Treeview inside combobox

Hi,

We are using a treeview inside combobox and it is working such a way that the child nodes will be populated only on click of parent nodes. That is working fine. What we need is we want the treeview to be populated only on combobox click. How we can acheive that?

Regards,
Jincy

Hi Jincymol,

One way to achieve this goal would be the following:

• The TreeView in the ComboBox is initially empty
• Handle the OnClientDropDownOpening event of the ComboBox and create the root Nodes of the TreeView (setting their ExpandModes to ServerSideCallback)

I hope this will get you started.
Sincerely yours,
Simon
the Telerik team

Hi,

Now we are loading the treeview on page_init event. What we expect is we have to load the treeview only on item requested event. We are using Q3 2008 version. Is this possible?

Regards,
Jincy

Hello Neil,

Load on demand with templates works only for non-AJAX controls. In other words, you cannot add a RadTreeView to the Items of the ComboBox if it is loading them via the Load on Demand mechanism.

Regards,
Simon
the Telerik team

Hi,

Can you please explain? Do you mean that it is not possible? now we are loading the treeview on init event of combobox. is it not possible to load the treeview when we click on combobox?

regards,
Jincy

Hi Jincymol,

What I meant was that RadTreeView as a Template of a ComboBox with Load on Demand is not achievable.

On the other hand, in a normal ComboBox, data bound on the server, you could put a RadTreeView as a Template as shown in this live demo.

Could you be a bit more specific on your goal? What do you mean by "...load the treeview when we click on combobox?"

Kind regards,
Simon
the Telerik team

We have a number of treeview-in-combo controls and, as suggested by Telerik support, we currently load the treeview on the init events of the combos; we then poplutate the treeview nodes on demand. However, the init event is "triggered" by page load and is causing a significant delay in loading some of our pages (and radWindows, where we also use them). We had understood that the new (Q3 version) of the controls allowed "lazy initialisation" - - ie that the combo would not initiate its Init event until the user clicked its dropdown arrow. But this appears not to be so - the init event is still firing on page load and delaying the loading. We are trying to discover how to take advantage of the new "lazy initialisation" to prevent these delays

Best regards,   Jincy

Hello Neil ,

The lazy initialization is a mechanism which works on the client.

For instance, Items in RadComboBox are actually initialized the first time the drop down is opened. Before that they do not exist. The result is that the page will load faster than usual (prior to the introduction of this mechanism).

I hope this sheds more light on the subject.

Regards,
Simon
the Telerik team

Thank you for trying to help but I had understood that. The problem is, it is not working on our system - the combos that we populate uising the Init event (because Telerik suggested using thtis even when we need to create a treeview in the combos) are all running on page load, making the pages very slow to load. I have now sent a project to Telerik support to demonstrate this problem, so I hope we will get a response using our own project
Best regards,   Neil

Hello Neil ,

As far as I have understood you until now you want to use RadTreeView in a Template of a RadComboBox and have Load On Demand at the same time. Currently this configuration is not supported by our controls. Actually, if you put *any* AJAX control inside the Template, the approach will not work.

We will still inspect your project in case there is something else which we are missing.

Sincerely yours,
Simon
the Telerik team