Error in UWP app

[dmitry-lt]

Windows 10 UWP app, submitted to the store, produces an error:

Cannot add instance of type 'Cimbalino.Toolkit.Behaviors.MultiBindingBehavior' to a collection of type 'Microsoft.Xaml.Interactivity.BehaviorCollection'.

On dev machine (in debug mode) everything works fine.

Lib version 2.4.1

[dmitry-lt]

Stacktrace of the error (only happens in release mode)

System.NullReferenceException: Arg_NullReferenceException
at Cimbalino.Toolkit.Behaviors.MultiBindingBehavior.Update() in D:\Users\Pedro\Dropbox\Projects\Cimbalino.Toolkit\src\cimbalino.toolkit (wp8)\behaviors\MultiBindingBehavior.cs:line 212
at Cimbalino.Toolkit.Behaviors.MultiBindingBehavior.OnAttached() in D:\Users\Pedro\Dropbox\Projects\Cimbalino.Toolkit\src\cimbalino.toolkit (wp8)\behaviors\MultiBindingBehavior.cs:line 166
at Microsoft.Xaml.Interactivity.Behavior.Attach(DependencyObject associatedObject)
at Microsoft.Xaml.Interactivity.BehaviorCollection.VerifiedAttach(DependencyObject item)
at Microsoft.Xaml.Interactivity.BehaviorCollection.BehaviorCollection_VectorChanged(IObservableVector1 sender, IVectorChangedEventArgs eventArgs) at Windows.Foundation.TypedEventHandler2.Invoke(TSender sender, TResult args)
at __Interop.Intrinsics.HasThisCall__22[TArg0](Object __this, IntPtr pfn, Object arg0, TArg0 arg1)
at __Interop.ReverseComStubs.Stub_5[TArg0,TArg1](Object __this, Void* unsafe_d, Void* unsafe_e, IntPtr __methodPtr)

[dmitry-lt]

The error seems to disappear if I uncheck Project properties -> Build -> Optimize code

[pedrolamas]

What version of Visual Studio are you using? Are you using the correct UWP XAML Behaviors (the one from this NuGet)?

[dmitry-lt]

Visual Studio 2017.

In my project.lock.json there is

"Cimbalino.Toolkit/2.4.1": {
"type": "package",
"dependencies": {
"Cimbalino.Toolkit.Core": "2.4.1",
"Microsoft.Xaml.Behaviors.Uwp.Managed": "1.1.0"
},

Only Cimbalino.Toolkit is referenced directly in the project References

[pedrolamas]

Please try to manually add the Microsoft.Xaml.Behaviors.Uwp.Managed package to your project and see if that makes any difference.

[dmitry-lt]

Manually adding Microsoft.Xaml.Behaviors.Uwp.Managed package does not make any difference.

If "Compile with .NET Native tool chain" and "Optimize code" are checked, I get this error. Unchecking those is a workaround.

[pedrolamas]

Oh, I just noticed you're using the MultiBindingBehavior: That's not available in UWP!!

Please ensure you add Cimbalino.Toolkit to all your projects that actually require it, it should then pick the correct assembly according to the platform!

[dmitry-lt]

How come it is not available? I've been using it for quite some time. What should I use instead?

For example, this article says it's available:

http://www.damirscorner.com/blog/posts/20160221-MultibindingInUniversalWindowsApps.html

[pedrolamas]

Sorry, though I wrote MultiBindingBehavior I was thinking on MultiApplicationBarBehavior; it's been a long day, so please just disregard my last comment...

I now start to remember this better, and you are correct when you say that this issue goes away when disabling .NET Native: the problem is that this behavior relies heavily on reflection and as such, can have .NET Native problems.

I need to research this further, but I'd advise in using compiled bindings (x:bind) function support as an alternative!

[pedrolamas]

@dmitry-lt can you share the XAML bit you have with this MultiBindingBehavior ?

[dmitry-lt]

<Image VerticalAlignment="Top" HorizontalAlignment="Center" Margin="0 5 0 5" Width="50" Height="50">
    <interactivity:Interaction.Behaviors>
        <behaviors:MultiBindingBehavior Converter="{StaticResource IconConverter}" PropertyName="Source">
            <behaviors:MultiBindingItem Value="{Binding Item}" />
            <behaviors:MultiBindingItem Value="{Binding Item.Enabled}" />
            <behaviors:MultiBindingItem Value="{Binding Item.Status}" />
            <behaviors:MultiBindingItem Value="{Binding Item.Type}" />
        </behaviors:MultiBindingBehavior>
    </interactivity:Interaction.Behaviors>
</Image>

[pedrolamas]

Ok, the solution will be to add a runtime exception so that we can use reflection over Image.Source property.

On the solution explorer, there's a Properties node in the UWP project for your app - expand it!

Inside you should find a Default.rd.xml file. Find where it says "" and add the following line below it:

<Type Name="Windows.​UI.​Xaml.​Controls.Image" Dynamic="Required All" Serialize="Require All" />

Rebuild the app with the "Compile with .NET Native tool chain" and "Optimize code" checked, and check again!

[dmitry-lt]

Hmm. There is no Default.rd.xml in my project. Anyway, I have already changed my code to not use MultiBindingBehavior (and handle it in view model instead).