EventTrigger on UserControl 'Loaded' not calling ICommand.Execute - wpf

Question

I'm trying to execute an ICommand (AsyncRelayCommand) on the loaded event of my UserControl using the Microsoft.Xaml.Behaviors.Wpf library.
<UserControl x:Class="..."
...
xmlns:Behaviors="http://schemas.microsoft.com/xaml/behaviors"
DataContext="{Binding ViewModel, Source={StaticResource ViewModelLocator}}">
<Behaviors:Interaction.Triggers>
<Behaviors:EventTrigger EventName="Loaded">
<Behaviors:InvokeCommandAction Command="{Binding LoadCommand}" />
</Behaviors:EventTrigger>
</Behaviors:Interaction.Triggers>
...
</UserControl>
The command property is called correctly, the Command class is created and it also calls correctly the CanExecute method (which returns true).
public override ICommand LoadCommand
{
get { return new AsyncRelayCommand(
async () => { /*never executed*/ },
() => return !this.IsLoading); // canExecute logic executed (true)
}
}
But it never calls the Execute method.
I believe I need somehow tell that I want the UserControl's event, but all examples are looking the same as mine.

Answer 1

I believe the design as described, does not adhere to separation of concerns between the user control and an external viewmodel.
I would instead use the Loaded event of the UserControl and create a specific dependency property on the control which the user will have bound the ICommand to when wiring up the control.
Example
#region public ICommand LoadCommand
/// <summary></summary>
public ICommand LoadCommand
{
get => GetValue(LoadCommandProperty) as ICommand;
set => SetValue(LoadCommandProperty, value);
}
/// <summary>
/// Identifies the LoadCommand dependency property.
/// </summary>
public static readonly DependencyProperty LoadCommandProperty =
DependencyProperty.Register(
"LoadCommand",
typeof(ICommand),
typeof(MainUserControl),
new PropertyMetadata(null));
#endregion public ICommand LoadCommand
private void MainUserControl_OnLoaded(object sender, RoutedEventArgs e)
=> LoadCommand?.Execute(null);