Routed Event Args Null

[Kevin Marois]

I have a user control with a custom Routed Event. I'm trying to pass event args:

public class NavigationViewFilterEventArgs : RoutedEventArgs
{
public List<LookupEntity> StatusFilters { get; private set; }

public List<LookupEntity> FilterItems { get; private set; }

public NavigationViewFilterEventArgs(RoutedEvent e, List<LookupEntity> statusFilters, List<LookupEntity> filterItems) :
    base(e)
{
    StatusFilters = statusFilters;
    FilterItems = filterItems;
}

}

Here's the UserControl code behind:

public static readonly RoutedEvent FilterExecutedEvent =
EventManager.RegisterRoutedEvent("FilterExecuted",
RoutingStrategy.Bubble,
typeof(RoutedEventHandler),
typeof(NavigationView));

public event RoutedEventHandler FilterExecuted
{
add { AddHandler(FilterExecutedEvent, value); }
remove { RemoveHandler(FilterExecutedEvent, value); }
}

private void RaiseFilterExecutedEvent()
{
var args = new NavigationViewFilterEventArgs(FilterExecutedEvent, StatusFilters, FilterItems);
RaiseEvent(args);
}

The control is on the Main Window:

<ctrls:NavigationView Grid.Row="7"
Caption="Companies"
StatusFilters="{Binding DataContext.CompanyStatusFilterItems,
ElementName=window, Mode=TwoWay,
UpdateSourceTrigger=PropertyChanged}">

<i:Interaction.Triggers>
    <i:EventTrigger EventName="FilterExecuted">
        <i:InvokeCommandAction Command="{Binding DataContext.CompanyFilterExecutedEventCommand, 
                                                    ElementName=window}"/>
    </i:EventTrigger>
</i:Interaction.Triggers>

</ctrls:NavigationView>

And finally the handler in the Main Window view model:

private ICommand _CompanyFilterExecutedEventCommand;
public ICommand CompanyFilterExecutedEventCommand
{
get
{
if (_CompanyFilterExecutedEventCommand == null)
_CompanyFilterExecutedEventCommand = new RelayCommand<NavigationViewFilterEventArgs>(p => CompanyFilterExecutedEventExecuted(p), p => CompanyFilterExecutedEventCanExecute());
return _CompanyFilterExecutedEventCommand;
}
}

private bool CompanyFilterExecutedEventCanExecute()
{
return true;
}

[Richard Deeming]

The problem isn't that the EventArgs object is null; it's that the EventArgs object isn't being passed as the command parameter to your RelayCommand. If you're using the Microsoft.Xaml.Behaviors.Wpf[^] package, you need to set PassEventArgsToCommand="True" on your <i:InvokeCommandAction> element. If you're using Prism, that will pass the event args automatically if the command parameter is not set. But that would use a different namepsace prefix on the InvokeCommandAction element. 6: Advanced MVVM Scenarios Using the Prism Library 5.0 for WPF | Microsoft Docs[^] Other platforms will have different approaches. There are quite a few documented on this SO thread: wpf - MVVM Passing EventArgs As Command Parameter - Stack Overflow[^]

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