Performance drop with ExplorerMode Thumbnails

2 posts, 0 answers
  1. Erick de
    Erick de avatar
    75 posts
    Member since:
    Feb 2010

    Posted 04 Mar 2016 Link to this post


    We're using your RadFileExplorer as imagepicker in our software and are trying to improve the performance of it.
    Some users don't sort their images into subfolders but puts all of their images in the root folder, with results high performance drop when not using pager with more than 2000 images in one folder (especially with slow internet connections).

    Without pager: 20 seconds until 2 minutes to load
    With pager: 5 until 10 seconds to load

    But still very slow, we're targeting to 2~3 seconds (maximal).

    It seems the thumbnail mode don't caches the generated views because the performance difference between grid and thumbnail modes is very huge, after first load as well. The grid mode seems loads within 1,5 seconds which thumbnail mode takes 5 until 10 seconds.

    How we can improve the performance of the FileExplorer with thumbnail mode?

  2. Vessy
    Vessy avatar
    1660 posts

    Posted 09 Mar 2016 Link to this post

    Hi Erick,

    The performance of FileExplorer when used in Thumbnails mode depends a lot on the quantity and the type of the loaded items. When FileExplorer is used in thumbnails mode it is creating the rendered thumbnails dynamically and it is expected that this process will be slow if there are many big images inside a folder. The created images are only visually resized image elements, loading the original image in themselves (thus the performance issue when the loaded images are big).

    Here are some steps you can go through in order to optimize the performance of your FileExplorer when used in Thumbnails mode:​
    • you can enable the FileExplorers's paging, decreasing the page size so the control will render less images at a time (in an Editor scenario you will need to edit the FileBrowser.ascx dialog
      <telerik:RadFileExplorer ID="RadFileExplorer1" runat="server" PageSize="10" AllowPaging="true">
          <Configuration ViewPaths="~/Images/big" />

    • you can implement your own thumbnails logic, passing the path to the desired thumbnails to each image object Url property. For example, you can use the approach provided on 14th of March in this forum thread.
    • you can use FileExplorer in grid explorer mode (the default one) and implement an image previewing feature similar to the one in this live demo (avoiding the rendering of all images on the page at the same time):
      <telerik:RadFileExplorer ID="RadFileExplorer1" runat="server" ExplorerMode="Default">
          <Configuration ViewPaths="~/root" />
    I hope the provided information will be helpful for you to achieve the desired functionality of the control.

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