Studio for Windows Phone

Very slow scrolling in RichTextBox

  •  Sequd163 said 1 year, 11 months ago:

    On devices
    HTC HD2 (WP 7.1)
    Nokia Lumia 710 (WP 7.1)
    Text scrolling flicker and moving very slow for any amount of text in text or html mode of control.
    We used your samle code "Input" replaced html from resources with our one. Formatting sample is also very slow in scrolling (rendering flickers).
    Is it exists any workaround for this or maybe you have any planned update for richtextbox performance.

  •  Greg Lutz80p said 1 year, 11 months ago:


    Yes, i’ve done a lot of work with RichTextBox and I agree scrolling performance is not as good as native ListBox on a device. In the emulator it’s comparable but on device it’s apparently slower. We will be investigating this more in the future, but unfortunately i don’t have any workarounds at this time.


  •  zaxbowow said 1 year, 6 months ago:

    Dear Greg,

    I see your reply is 4 months old. Have any fixed been implemented?

    I downloaded the RichTextBox control for Windows Phone and added it to my project. The control by all appearance functions quite excellently for rendering and editing WYSIWIG html. But the usability of this control – the fact that it is nearly completely unresponsive to scrolling, casts a dark shadow over the suitability of this control for any real-world application.

    Are there any workarounds (for example hosting the control, within another) , that might make it usable in my application? I otherwise like it and was saddened to see this great limitation.


    – Eric

  •  Greg Lutz80p said 1 year, 6 months ago:

    Hi Eric,

    We are aware of the performance scrolling large text. A possible workaround is to put RichTextBox into a ScrollViewer to take advantage of the hardware accelerated control.

       <c1:C1RichTextBox Height="1000" />

    You don’t have to specify a height on RTB, but in some samples i found it works better. This workaround sacrifices somethings like scroll thumb and scroll-to-caret during editing, but for some scenarios it might be better than nothing,


  •  zaxbowow said 1 year, 6 months ago:

    Thanks for the prompt reply, Greg. I’ll try that out with an open mind.

    I’m a little concerned however – I’m seeing my app crash when using the C1 RichTextBox control in the small amount of testing I’ve done. I hope it gets an update… this control may not be ready for prime time in its current form. I can’t release my app with this RTF control if hosting it will make my app unstable.


    – Eric

  •  Jason said 2 months, 1 week ago:

    Hi Greg,

    Thanks for the RichTextBox control, we are using it in one of our apps and works great so far. The only issue is about the scrolling. When the HTML content is quite large than usual, the whole screen slows down and scrolling becomes very slow.

    We have tried wrapping RTB with scrollviewer as well, but the content gets clipped due to the scrollviewer. Wondering if there’s any update on this issue, since it’s been about 2 years. Any hints/ideas will be very helpful because we are struggling to get a web browser control working with a large amount of HTML content.


  •  Reema176p said 2 months ago:


    Apologies for the delay in response.

    We could observe the behaviour at our end as well.

    We have escalated the issue to the concerned team and will get back to you as soon as we have any update from their side regarding the same.


  •  Reema176p said 1 month, 2 weeks ago:


    Just an Update :
    The development team is still investigating the scroll performance of C1RichTextBox.
    As per them, it is a very difficult issue and would need big changes to C1RichTextBox.

    The resolution to this issue can be expected in the future builds of the controls.


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