Events not being handled from a user control and main form - wpf

Question

I am attempting to handle an event in the application main form where said event is being raised from a user control populated on the main form. I've defined an Interface for the event which is being implemented in both the Main Form and the User Control. I'm using MvvmLight from GalaSoft for the MVVM support.
The main form code behind indicates that the event is attached, but when I do the check in the user control, it indicates that there is no handler attached to the event, so obviously, it won't ever get to the handler.
Any help would be appreciated.
The interface I've defined is pretty basic:
Public Interface IEventFiring
Event EventFiring(sender As Object)
End Interface
My Main Form Xaml looks like this:
<Window x:Class="MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:EventFiringFromContolToMainForm"
xmlns:efc="clr-namespace:EventFiringControl;assembly=EventFiringControl"
Title="MainWindow">
<Window.DataContext>
<local:MainWindowViewModel/>
</Window.DataContext>
<StackPanel>
<TextBox Text="{Binding StatusText, Mode=OneWay}"
Height="25"
Margin="5"/>
<Separator Margin="5"/>
<efc:UserControl1/>
</StackPanel>
</Window>
The Code Behind is:
Imports EventFiringControl
Class MainWindow
Implements IEventFiring
Public Sub New()
' This call is required by the designer.
InitializeComponent()
' Add any initialization after the InitializeComponent() call.
AddHandler EventFiring, AddressOf EventFiringSub
If EventFiringEvent Is Nothing Then
CType(DataContext, MainWindowViewModel).StatusText = "Event did NOT Attach!!"
Else
CType(DataContext, MainWindowViewModel).StatusText = "Event Attached"
End If
End Sub
Public Event EventFiring(sender As Object) Implements IEventFiring.EventFiring
Private Sub EventFiringSub()
CType(DataContext, MainWindowViewModel).StatusText = "Event Fired"
End Sub
End Class
The view model for the Main Form is:
Imports GalaSoft.MvvmLight
Public Class MainWindowViewModel
Inherits ViewModelBase
Private _statusText As String
Public Property StatusText As String
Get
Return _statusText
End Get
Set(value As String)
_statusText = value
RaisePropertyChanged(Function() StatusText)
End Set
End Property
End Class
Now for the User Control.
Xaml file is:
<UserControl x:Class="UserControl1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:local="clr-namespace:EventFiringControl"
mc:Ignorable="d"
d:DesignHeight="300" d:DesignWidth="300">
<UserControl.DataContext>
<local:EventFiringViewModel/>
</UserControl.DataContext>
<Grid>
<Button Content="Cancel" Command="{Binding CancelCommand}" Height="50"/>
</Grid>
</UserControl>
The code behind is:
Public Class UserControl1
Public Sub New()
' This call is required by the designer.
InitializeComponent()
' Add any initialization after the InitializeComponent() call.
End Sub
End Class
Finally, the View Model for the User Control is:
Imports GalaSoft.MvvmLight.Command
Imports GalaSoft.MvvmLight
Public Class EventFiringViewModel
Inherits ViewModelBase
Implements IEventFiring
Public ReadOnly Property CancelCommand As RelayCommand
Get
Return New RelayCommand(Sub() CancelSub())
End Get
End Property
Private Sub CancelSub()
If EventFiringEvent IsNot Nothing Then
RaiseEvent EventFiring(Me)
End If
End Sub
Public Event EventFiring(sender As Object) Implements IEventFiring.EventFiring
End Class