Radcombobox render items slowly with large itemsource

[Lieu]

Hi guys,

I'm not sure if anyone get the same problem with me. My client ask to have a radcombobox with around 4000 records in itemsource. The combobox should allow filtering as well. Of course it is possible, but it is very slow to render that much item in the popup, and also filter when user start typing something in the textbox.

 

 <telerik:RadComboBox x:Name="MyRadComboBox" Grid.Column="1" ItemsSource="{Binding Source={StaticResource MyItemSource}}" Text="{Binding CurrentNameFilter, Mode=TwoWay}" CanAutocompleteSelectItems="False"                                 IsEditable="True" IsFilteringEnabled="True" OpenDropDownOnFocus="True" TextSearchMode="Contains"/>

MyItemSource is about 4000 records. And right now it take very long time to show the popup list item when user focus in the comboxbox. It is also very slow when user type something and want to see the suggestion list.

I've been researching but didn't see any solution yet. Please help me. My client keep complaining about the performance.

Thanks in advance.

[Konstantina]

Hello Lieu,

For optimizing the performance of the RadComboBox you could use virtualization - more information you could find in this help article.
However, at the moment RadComboBox does not support virtualization and filtering (you mentioned that your client uses this feature). Nevertheless, please check this forum thread where you could find a sample project how to load items on demand.

Hope this information helps.

Regards,
Konstantina
the Telerik team

[danparker276]

I was just browsing to see if there was any update to this.  I currently just use a listbox under a textbox and it works pretty well.
Below is a link to an example and some code.
http://xamlui.com/ComboBox.htm 

I hope the combobox can be updated to support this someday.  It's very useful to many business applications and there are several times when I need this.

[danparker276]

Also if you want to vote on this issue on the issue tracker, it's here:
http://www.telerik.com/support/pits.aspx#/details/Issue=5568 

There are 22 votes right now.  I'm not even sure why you'd even want virtualization if you can't filter it.

[danparker276]

I'm not sure if this always happened, but even with virtualization when I press a key in the combo box, it takes about 2-3 seconds for the key to show with a large amount of data.  Scrolling is fast and works great, but if I want to type anything in, this box is useless.  I'm switching to the autocomplete box which works a lot faster.

[Konstantina]

Hello,

The AutoCompleteBox supports filtering and autocomplete and it is virtualized by default, so it is the best choice for these scenarios. You could check also its online documentation for more information how to implement it.

Greetings,
Konstantina
the Telerik team

[danparker276]

I actually don't even care about the filtering and don't have it on.  I keep trying to use the auto-complete, but it's still filled with bugs and doesn't do exactly what I want.  On major thing is that it doesn't auto-complete and move to the next control when I hit tab with the auto-complete box.  I have to hit tab twice.  The Combo-box auto-complete works perfect.

I think most people would just use a regular combobox for a small amount of items.  I don't see the use of making this a telerik control if it can't handle a large amount of data.  I've just decided to use a textbox and have listbox dropdowns under the textbox.  That works great because listboxes are virtualized and very fast.  I wish you could just make a basic control like that.

I know that some of these things might seem very minor, but I and I would think most of your customers make internal business applications.  People who are typing in the same or similar stuff everyday.  Keyboard input with tabbing is very important to my customers.  Reducing the amount of keystrokes and the speed is very important.  Much of it is data entry

[Vladi]

Hi,

As previously mentioned in the current version of RadComboBox filtering with virtualization is not supported, and if you have more then couple of thousands of items there may be some performance issues.

About the RadAutoCompleteBox issue when item is selected with the Tab keyboard key, we looked into the issue and it seems there is a bug in the control that we will do our best to fix as soon as possible.

All the best,
Vladi
the Telerik team

[danparker276]

My filtering is off.  I don't need to use that.  The virutalization is fine, I can scroll up and down really fast.  The only problem is typing in the textbox sometimes takes about 5 seconds per keystroke because it's trying to auto-complete.  Maybe the auto-complete is considered filtering, so that's why it's slow.  That sounds like the case and I'll just use auto-complete.

[Vladi]

Hello,

When the RadComboBox control is in its editable mode by setting its IsEditable property and the VirtualizingStackPanel is set the scrolling the items in the drop down portion of the control doesn't experience performance issues but the matching logic when you type in the control i not effected by that vurtialization. There shouldn't be any major performance issues when using editable RadComboBox with up to 20 000 items in its ItemsSource. If the collection of items is bigger then that there maybe some performance issues when typing in the control.

We apologize for any inconvenience that this maybe causing.

Regards,
Vladi
the Telerik team