Speeding Up First Load

[Aaron]

Hi,

I have a RadComboBox on my window that gets popuated with about 1400 business objects.  The combo box itself uses a custom data template, so that I can display several different properties in the combo box items at the same time.

I'm populating the Items Source of the combo box in Page_Load.  It's taking about 1/2 a second to get the collection of objects from the data store. 

What I've noticed, however, is that the first time the combo box is clicked by the user, there is about a 6 second delay until it displays its items.  Since the items source has already been populated, I assume that during this time, RadComboBox is drawing all of its items based on the customized data template.  After this initial delay, subsequent clicks of the combobox produce pretty-near instantaneous results.

I'm wondering if there is a way to get the RadComboBox to do this initial work before the UI is drawn, so that the user doesn't have the experience of a non-responsive UI.  They won't mind waiting longer for the inital page to load, as long as it's responsive once it comes up.

Thanks.

[Pana]

Hello Aaron,

The RadComboBox uses a StackPanel by default. If you are displaying so much objects in the combo you may try to set its ItemsPanel to VirtualizingStackPanel. You can find more information about how to enable the virtualization here.

Greetings,
Pana
the Telerik team

[Aaron]

Amazing.

Thank you.

Aaron