Comparison to RadComboBox

6 posts, 0 answers
  1. Geoff
    Geoff avatar
    5 posts
    Member since:
    Jul 2012

    Posted 03 Feb 2013 Link to this post

    Hello -

    I'm having some trouble understanding when I should use a RadDropDownList versus a RadComboBox.  At the moment it appears to be a trimmed version of RadComboBox with less available features.  This would be fine if does everything that's needed and does it faster with less overhead.  My own performance testing shows it doesn't have much less overhead, atleast in terms of viewstate size.   Viewstate size would be my biggest complaint of the ComboBox.

    For default settings on each:
    RadComboBox had the largest viewstate, RadDropDownList was 10% less, DropDownList was 50% less.
    RadDropDownList had the largest page size, RadComboBox was 15% less, DropDownList was 50% less.

    The page size difference was due to rddlItemText style lacking in RadComboBox.  With gzip compression page size is mostly a non-issue, but I'm quite concerned that it only has a 10% improvement in lowering viewstate footprint.

    Is this going to be improved further? Or is there some other purpose for this control I'm just not seeing?

    Thanks.
  2. Bozhidar
    Admin
    Bozhidar avatar
    1102 posts

    Posted 06 Feb 2013 Link to this post

    Hello Geoff,

    Your observations are correct.

    The RadDropDownList was indeed intended to target the cases where you need the simple functionality of the ComboBox, while keeping the overhead to a minimum. Most of this is explained in the following blog post:
    http://blogs.telerik.com/blogs/13-02-06/meet-the-better-performing-and-more-lightweight-dropdownlist-for-asp.net-ajax

    In terms of performance and reduced overhead we targeted the following fields:
    1. The size of the javascript files sent to the browser
    2. The size of the stylesheets
    3. The page size
    4. Viewstate
    We also have included a better keyboard support (with handling for the PageUp/Down keys for instance), and a new feature called VirtualScrolling (replacing LoadOnDemand), which makes the faster when dealing with large sets of data (with both server and client binding).

    The reduced size of the .js and .css files is obvious - less than 50% (not counting the common scripts which are loaded for every control, like Core.js etc.). As for the page size, we examined it further and came to the conclusion that we can improve it so that the item doesn't include the additional "span class=rddlItemText" element unless an ImageUrl is set. This will be fixed for the official 2013Q1 release.

    We also investigated the ViewState size of both controls in different settings. Our tests show that the amount of ViewState depends on the way you bind the control. With declarative binding to an ASP.NET SqlDataSource we also registered a 10% improvement. However in other binding scenarios(like binding to a list from CodeBehind) the amount of ViewState dropped by 40-50%. We will however look further into this and do our best to reduce the ViewState even further.

    For your feedback and involvement I've updated your Telerik points.

    Greetings,
    Bozhidar
    the Telerik team
    If you want to get updates on new releases, tips and tricks and sneak peeks at our product labs directly from the developers working on the RadControls for ASP.NET AJAX, subscribe to their blog feed now.
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  4. Geoff
    Geoff avatar
    5 posts
    Member since:
    Jul 2012

    Posted 06 Feb 2013 Link to this post

    Very helpful.  Thank you.
  5. Dave
    Dave avatar
    36 posts
    Member since:
    Jan 2008

    Posted 20 Feb 2013 Link to this post

    I just downloaded the new version of the RadControls and was also curious about the differences between the RadComboBox and the new DropDownList control. Is it just a matter of the DropDownList being more lightweight than the RadComboBox or are there other differences as well? When should we choose one over the other? Why didn't you guys just choose to make the RadComboBox more lightweight instead of introducing a new control? Just curious. Thanks in advance.
  6. Joel
    Joel avatar
    19 posts
    Member since:
    Oct 2011

    Posted 20 Feb 2013 Link to this post

    Also are you enabling the behavior microsoft's drop down lists have when using mobile devices?.

    When you tap microsoft's one, the list of options is displayed like in a popup window, making selection even easier on those small screens.


    Regards!!
  7. Bozhidar
    Admin
    Bozhidar avatar
    1102 posts

    Posted 21 Feb 2013 Link to this post

    Hello,

    We can't achieve the same level of compactness and simply make the RadComboBox more lightweight without removing some of it's functionality, which is something we don't want to do. As stated earlier, the goal was less ViewState, less page size and lest scripts and styles loaded on the page, and at the same time provide a control that's very easy to configure. 

    When should we choose one over the other? - you can find the answer to this question in my previous reply here, as well as the following articles:
    http://blogs.telerik.com/blogs/13-02-06/meet-the-better-performing-and-more-lightweight-dropdownlist-for-asp.net-ajax
    http://www.telerik.com/help/aspnet-ajax/dropdownlist-difference-from-radcombobox.html

    As for Joel's question - On a mobile device RadDropDownList looks and behaves the same as on a desktop machine. The popup window feature is not considered at the moment.
     

    Kind regards,
    Bozhidar
    the Telerik team
    If you want to get updates on new releases, tips and tricks and sneak peeks at our product labs directly from the developers working on the RadControls for ASP.NET AJAX, subscribe to their blog feed now.
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