Home / Community & Support / Developer Productivity Tools Forums / WPF > ComboBox > Disable ComboBox Auto Scroll Behaviour

• Mike

  Posted on Dec 3, 2011 (permalink)

  Hello,
  
  I am wondering if it is possible to disable the autoscrolling behaviour in a combobox drop down (e.g. if last visible item in dropdown is selected the list jumps one item to bring the next item into view). Unfortunately this behaviour also fires when the mouse is hovered over the last visible item.
  
  This is very irritating for my users where the combobox is located near the bottom of the screen and the list is displayed upwards. What usually happens is that the user clicks the combobox arrow, the list is displayed upwards and as soon as the mouse is moved up the list (passing the last item in the list which is not fully displayed) the whole list jumps by one. An even worse scenario is where the user scrolls the desired item into view (desired item is now at bottom of visible drop down) but as soon as he/she hovers over the item to click it it jumps up by one.
  
  Is there an option / way to disable this?
  
  Many Thanks,
  
  Mike

  Reply

• Valeri Hristov Valeri Hristov

  Posted on Dec 6, 2011 (permalink)

  Hi Mike,
  
  Unfortunately there is no way to disable this behavior. You could "hide" it to large extent by setting such MaxDropDownHeight on RadComboBox so it does not display some of its items partially. This depends on the themes, so I guess you should experiment a little until you find the right number. For example, MaxDropDownHeight=205 corrected the problem on my side (using the default theme).
  
  Greetings,
  Valeri Hristov
  the Telerik team

  Explore the entire Telerik portfolio by downloading the Ultimate Collection trial package. Get it now >>

  Reply

• Mike

  Posted on Dec 26, 2011 (permalink)

  Thanks Valerie, I did notice (as you suggest) that it does get better with adjusting MaxDropDownHeight. I am a bit concerned though that this might not work for all DPI settings?

  Reply

• Valeri Hristov Valeri Hristov

  Posted on Dec 28, 2011 (permalink)

  I performed a quick test with 100%, 125% and 150% (the standard settings in Windows 7 control panel) and the WPF application UI scaled nicely without breaking the workaround I suggested.
  
  By the way the auto scroll is a "feature" of the standard ScrollViewer in WPF - the standard WPF ComboBox also has it, in lower extent, however, because its dropdown is evenly sized with its items...
  
  Greetings,
  Valeri Hristov
  the Telerik team

  Explore the entire Telerik portfolio by downloading the Ultimate Collection trial package. Get it now >>

  Reply

• Mike

  Posted on Dec 29, 2011 (permalink)

  Thanks for trying this out, much appreciated.

  Reply

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