radComboBox performance issue, very slow?

2 posts, 0 answers
  1. Rob Ainscough
    Rob Ainscough avatar
    172 posts
    Member since:
    Jan 2010

    Posted 13 Aug 2013 Link to this post

    I'm having a problem with a radComboBox bound to an observable collection that contains about 25,000 object entries ... in fact performance starts to get very bad around 3000+ entries (IsEditable = True and Binding Mode= TwoWay).  The performance problem is noticeable when I click on the drop down arrow to display entries in the dropdown list ... nothing happens, no list and it's unresponsive ... 30-45 seconds (a huge delay) before the list will appear showing my items.  Once the items finally display, scrolling the list is VERY VERY slow.  Even when I close the dropdown list it's slow.

    As a test I set IsEditable=False ... this made no difference in the performance.

    So as another test, I replaced the radComboBox with Microsoft ComboBox and performance was just as bad.

    So I guess my question is -- is there anyway to improve the performance of radComboBox or MS ComboBox?

    Thanks, Rob.
  2. Vladi
    Admin
    Vladi avatar
    744 posts

    Posted 16 Aug 2013 Link to this post

    Hello,

    In the current version of RadComboBox the virtualization is not turned on by default. In order to turn it on all you need to do is set the ItemsPanel of the control to VirtualizingStackPanel.

    Th next code snippet shows how to set the VirtualizingStackPanel to the ItemsPanel of the Combobox control:
    <telerik:RadComboBox ...>
        <telerik:RadComboBox.ItemsPanel>
            <ItemsPanelTemplate>
                <VirtualizingStackPanel/>
            </ItemsPanelTemplate>
        </telerik:RadComboBox.ItemsPanel>
    </telerik:RadComboBox>

    It is worth mentioning that filtering with virtualization is not supported in the current version of the control. Fortunately we have another control RadAutoCompleteBox which is virtualized by default and supports filtering.

    Regards,
    Vladi
    Telerik
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