RadDataBoundListBox scrolling

[Janier]

Hi,

I  recently bought the Rad Controls because of the superb suite of controls and functionality I needed for next app. I am very happy so far. I am using the version: v.2011.3.920.2040 which looks to be the latest build. I installed the Mango Telerik Samples app on my Samsung Focus running Mango. When I go to the DataBound ListBox samples (or JumpList for that matters) I noticed the scroll jumping as I flick thru the list. When I go to the Comparison pivot item that gives you the option to compare the RadDataBound ListBox with the standard one, I notice the standard listbox scrolls smoother than the Rad Control.

Is that a known issue?

Thanks,
Janier Davila

[Deyan]

Hello Janier,

Thanks for writing.

I am not quite sure that I correctly understand your point here. In our latest version of RadDataBoundListBox we plug into the native ScrollViewer and thus use its support for off-thread scrolling which makes the scrolling experience as smooth as possible. If your note here targets the frequency in which the Scrollbar is updated - yes, this is not as smooth as in the standard ListBox control because in the standard control the scrollbar is also updated off-thread (on the newly introduced Manipulation thread). This is possible only in case the entire scrolling logic is implemented by inheriting from the ScrollViewer's interfaces which - currently - are internal and thus not accessible for third party developers. In general, this is not an issue, but a limitation that with the current Windows Phone 7 API we are not able to overcome. We still believe though that having the smooth and responsive scrolling experience, a faster UI virtualization engine and a bigger feature set make RadDataBoundListBox a great alternative over the standard one.

Do not hesitate to get back to us in case you have further questions or feedback to share.

All the best,
Deyan
the Telerik team

[Janier]

Deyan,

Thanks for replying.

I want to start by saying that I love the RadDataBoundListBox control. I was not saying that I  prefer it over the standard. When I saw simple thinsg like EmptyContent property and as fancy as the vitualization engine, I was hooked; bought the suite right away. Maybe I did not make myself clear enough.

But you did. Yes, I was referring to the Scrollbar, which makes jumps while scrolling, not the scrolling itself. My appologies. Fair enough, you explained the issue well.

Thank you,
Janier Davila

[Deyan]

Hi Janier,

Thanks for writing back.

Your point is correct. Since the API of the scrolling logic that the standard ListBox uses is not completely open, we cannot fully integrate our control with it and therefore there is a slight difference in the experience.

Let us know if you have any further questions or need assistance.

Regards,
Deyan
the Telerik team