EventToCommandBehavior for 3rd party Control Error

[Shannon-roos]

I am using a Syncfusion Numeric Entry control for .net MAUI and trying to get the EventToCommandBehavior to invoke the Delegate Command in the ViewModel.

However when I add the EventToCommandBehavior to the control I get an exception when navigating to the view (or opening the dialog).

System.ArgumentException: Expression of type 'Syncfusion.Maui.Inputs.NumericEntryValueChangedEventArgs' cannot be used for parameter of type 'System.EventArgs' of method 'Void Invoke(System.Object, System.EventArgs)' (Parameter 'arg1')

The code block for the control in question is,

<inputs:SfNumericEntry HorizontalOptions="Fill"
                          BackgroundColor="{DynamicResource ButtonBgColor}"
                          HorizontalTextAlignment="Center"
                          Margin="10"
                          x:Name="NumberInput"
                           MaximumNumberDecimalDigits="0"
                          Value="{Binding InventoryToSplit.Pieces, Mode=TwoWay, TargetNullValue='0'}"
                          ValueChangeMode="OnLostFocus">

       <inputs:SfNumericEntry.Behaviors>

           <prism:EventToCommandBehavior EventName="ValueChanged"
                                         Command="{Binding NewInventoryPiecesChangedCommand}"
                                         EventArgsParameterPath="NewValue"
                                         EventArgsConverter="{StaticResource PrismDefaultEventArgsConverter}" />
       </inputs:SfNumericEntry.Behaviors>


   </inputs:SfNumericEntry>

I've tried with and without the EventArgsParameterPath and converter with no love...

Doing the same thing with a basic Entry Control works fine. (ignore the event name differences this was just for testing)

<Entry Text="{Binding InventoryToSplit.WeightNetKgActual, Mode=TwoWay}"
        HorizontalTextAlignment="Center"
        FontSize="20"
        TextColor="White"
        Keyboard="Numeric"
    
        BackgroundColor="#2c343b">
     <Entry.Behaviors>

         <prism:EventToCommandBehavior EventName="TextChanged"
                                       Command="{Binding NewInventoryPiecesChangedCommand}"
                                       EventArgsParameterPath="NewTextValue"
                                       EventArgsConverter="{StaticResource PrismDefaultEventArgsConverter}" />
     </Entry.Behaviors>
 </Entry>

I assume the args for the SfNumericEntry ValueChanged event (NumericEntryValueChangedEventArgs) are not inherited from the System.EventArgs so Prism is freaking out... Just wondering what, if anything I can do about it?

I don't recall having this issue in Xamarin Forms so just checking if something has changed that I've missed.

Cheers

-- Full Stack Trace Below --

{Prism.Mvvm.ViewCreationException: Unable to create Dialog 'SplitInventoryDialogView'.
 ---> Prism.Ioc.ContainerResolutionException: An unexpected error occurred while resolving 'Company.Scanner.MAUI.Dialogs.Views.SplitInventoryDialogView'
 ---> System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation.
 ---> System.ArgumentException: Expression of type 'Syncfusion.Maui.Inputs.NumericEntryValueChangedEventArgs' cannot be used for parameter of type 'System.EventArgs' of method 'Void Invoke(System.Object, System.EventArgs)' (Parameter 'arg1')
   at System.Dynamic.Utils.ExpressionUtils.ValidateOneArgument(MethodBase method, ExpressionType nodeKind, Expression arguments, ParameterInfo pi, String methodParamName, String argumentParamName, Int32 index)
   at System.Linq.Expressions.Expression.ValidateOneArgument(MethodBase method, ExpressionType nodeKind, Expression arg, ParameterInfo pi, String methodParamName, String argumentParamName)
   at System.Linq.Expressions.Expression.Call(Expression instance, MethodInfo method, Expression arg0, Expression arg1)
   at Prism.Behaviors.EventToCommandBehavior.AddEventHandler(EventInfo eventInfo, Object item, Action`2 action) in D:\a\Prism\Prism\src\Maui\Prism.Maui\Behaviors\EventToCommandBehavior.cs:line 194
   at Prism.Behaviors.EventToCommandBehavior.OnAttachedTo(BindableObject bindable) in D:\a\Prism\Prism\src\Maui\Prism.Maui\Behaviors\EventToCommandBehavior.cs:line 165
   at Microsoft.Maui.Controls.Behavior`1[[Microsoft.Maui.Controls.BindableObject, Microsoft.Maui.Controls, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]].OnAttachedTo(BindableObject bindable) in /_/src/Controls/src/Core/Interactivity/Behavior.cs:line 68
   at Microsoft.Maui.Controls.Behavior.Microsoft.Maui.Controls.IAttachedObject.AttachTo(BindableObject bindable) in /_/src/Controls/src/Core/Interactivity/Behavior.cs:line 32
   at Microsoft.Maui.Controls.AttachedCollection`1[[Microsoft.Maui.Controls.Behavior, Microsoft.Maui.Controls, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]].InsertItem(Int32 index, Behavior item) in /_/src/Controls/src/Core/Interactivity/AttachedCollection.cs:line 53
   at System.Collections.ObjectModel.Collection`1[[Microsoft.Maui.Controls.Behavior, Microsoft.Maui.Controls, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]].Add(Behavior item)
   at System.Reflection.MethodBaseInvoker.InterpretedInvoke_Method(Object obj, IntPtr* args)
   at System.Reflection.MethodBaseInvoker.InvokeDirectByRefWithFewArgs(Object obj, Span`1 copyOfArgs, BindingFlags invokeAttr)
   --- End of inner exception stack trace ---
   at DryIoc.Interpreter.TryInterpretAndUnwrapContainerException(IResolverContext r, Expression expr, Object& result) in /_/src/DryIoc/Container.cs:line 3073
   at DryIoc.Container.ResolveAndCacheKeyed(Int32 serviceTypeHash, Type serviceType, Object serviceKey, IfUnresolved ifUnresolved, Object scopeName, Type requiredServiceType, Request preResolveParent, Object[] args) in /_/src/DryIoc/Container.cs:line 558
   at DryIoc.Container.DryIoc.IResolver.Resolve(Type serviceType, Object serviceKey, IfUnresolved ifUnresolved, Type requiredServiceType, Request preResolveParent, Object[] args) in /_/src/DryIoc/Container.cs:line 469
   at DryIoc.Resolver.Resolve(IResolver resolver, Type serviceType, Object[] args, IfUnresolved ifUnresolved, Type requiredServiceType, Object serviceKey) in /_/src/DryIoc/Container.cs:line 8673
   at Prism.Container.DryIoc.DryIocScopedProvider.Resolve(Type type, ValueTuple`2[] parameters) in /_/src/Prism.Container.DryIoc/DryIocScopedProvider.cs:line 54
   --- End of inner exception stack trace ---
   at Prism.Container.DryIoc.DryIocScopedProvider.Resolve(Type type, ValueTuple`2[] parameters) in /_/src/Prism.Container.DryIoc/DryIocScopedProvider.cs:line 58
   at Prism.Container.DryIoc.DryIocScopedProvider.Resolve(Type type) in /_/src/Prism.Container.DryIoc/DryIocScopedProvider.cs:line 41
   at Prism.Mvvm.ViewRegistryBase`1[[Microsoft.Maui.Controls.BindableObject, Microsoft.Maui.Controls, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]].CreateView(IContainerProvider container, String name) in D:\a\Prism\Prism\src\Prism.Core\Mvvm\ViewRegistryBase{TBaseView}.cs:line 55
   --- End of inner exception stack trace ---
   at Prism.Mvvm.ViewRegistryBase`1[[Microsoft.Maui.Controls.BindableObject, Microsoft.Maui.Controls, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]].CreateView(IContainerProvider container, String name) in D:\a\Prism\Prism\src\Prism.Core\Mvvm\ViewRegistryBase{TBaseView}.cs:line 78
   at Prism.Dialogs.DialogServiceBase.ShowDialog(String name, IDialogParameters parameters, DialogCallback callback) in D:\a\Prism\Prism\src\Maui\Prism.Maui\Dialogs\DialogServiceBase.cs:line 30
--- End of stack trace from previous location ---
   at Company.Scanner.MAUI.Extensions.IDialogServiceExtensions.ShowSplitInventoryDialogAsync(IDialogService dialogService, String title, String message, IInventory inventoryToSplit) in C:\Users\Shannon\Documents\CompanyRepos\Project\Company.Scanner.MAUI\Extensions\IDialogServiceExtension.cs:line 443
   at Company.Scanner.MAUI.Pages.ViewModels.InventoryEnquiryViewModel.onSplitInventoryCommand() in C:\Users\Shannon\Documents\CompanyRepos\Project\Company.Scanner.MAUI\Pages\ViewModels\InventoryEnquiryViewModel.cs:line 216}

[dansiegel]

Have you tried adding a Catch on the Command?

var myCommand = new DelegateCommand(() =>
{
    // Do something
}).Catch(ex =>
{
    // Handle the exception...
});

If you know what the actual exception is you can specify that for the Command. I'm not sure what your PrismDefaultEventArgsConverter is, but it looks like this is the real error:

System.ArgumentException: Expression of type 'Syncfusion.Maui.Inputs.NumericEntryValueChangedEventArgs' cannot be used for parameter of type 'System.EventArgs' of method 'Void Invoke(System.Object, System.EventArgs)' (Parameter 'arg1')

From this my guess is that your converter is expecting EventArgs which wouldn't have the NewTextValue path while the NumericEntryValueChangedEventArgs would.

[Shannon-roos]

Not sure why the converter is even there. Removing it doesn't fix the issue however.

I tried adding the catch on the DelegateCommand however it never even gets to the constructor. The error is thrown when trying to Show the Dialog (.ShowDialogAsync).

Interestingly if I swap out to the MAUI Community Toolkit's EventToCommandBehavior and specify the x:TypeArguments to be the NumericEntryValueChangedEventArgs it works ok...

    <inputs:SfNumericEntry.Behaviors>

        <toolkit:EventToCommandBehavior x:TypeArguments="inputs:NumericEntryValueChangedEventArgs"
                                        EventName="ValueChanged"
                                      Command="{Binding NewInventoryPiecesChangedCommand}"
                                     
                                      />
    </inputs:SfNumericEntry.Behaviors>

If you want to look into this further to help Prism I can put together a demo but I have working workarounds currently so I'm happy (enough).

Cheers again.