RadTreeView generates an error: "object reference not set to an instance of an object" in XAML.

3 posts, 0 answers
  1. Eugene
    Eugene avatar
    83 posts
    Member since:
    Jan 2016

    Posted 22 Apr Link to this post

    I try to use RadTreeView in my WPF MVVM Prism 6 application project. But when I put RadTreeView in UserControl area then it is underlined with blue wavy line and if I move the mouse cursor to this line the next error message is displayed: "Object reference not set to an instance of an object". I've added references to the following assemblies: Telerik.Windows.Controls, Telerik.Windows.Controls.Navigation, Telerik.Windows.Controls.Data. But I have the abovementioned error. What the reason of it. Please help me eliminate this error situation.
  2. Milena
    Milena avatar
    193 posts

    Posted 25 Apr Link to this post

    Hi Eugene,

    I am sorry to hear about the issues you are experiencing.

    Could you tell us if this error message is visible only in design time and you can run the project without throwing exception at runtime? 

    One of the possible reasons for seeing this error message could be the cache which is created by the Visual Studio, so you can try to:
    1. clean and rebuild the project. 
    2. or delete manually the bin and obj folders then rebuild the project  - this will ensure that all unnecessary files will be deleted.

    If the issue is connected to the Visual Studio designer, you can also do the following:
    1) close all visual studio instances.
    2) go to  C:\Users\<username>\AppData\Local\Microsoft\VisualStudio\<visual_studio_version,for_example_12.0>\Designer\ShadowCache and delete the folders there - this is the cache of VisualStudio's designer.

    If none of this helps, we will need more detailed information to further investigate the reasons behind the behavior (e.g. the version of your Visual Studio, if you are using third party extensions for Visual Studio, etc.). Also it would be great if you could send us an isolated project  where the issue appears. This will allow us to test it and further investigate the case.

    I am looking forward to helping you solve this issue.

    Do you need help with upgrading your AJAX, WPF or WinForms project? Check the Telerik API Analyzer and share your thoughts.
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  4. Eugene
    Eugene avatar
    83 posts
    Member since:
    Jan 2016

    Posted 25 Apr in reply to Milena Link to this post

    This error message disappeared when I add next control in XAML after RadTreeView. But today morning it appeared just after XAML markup had been loaded. But after I cleaned and rebuilt the solution the error message "Object reference not set to an instance of an object" about RadTreeView was disappeared.
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