WPFToolkit Wizard binding Commands for the Next/Previous buttons. (MVVM)

Question

I am trying to use the WPFToolkit.Wizard in an application using the MVVM design model.

RIght now I am having difficulties binding a RelayCommand (inherits from ICommand) to the Next/Previous/Finish buttons.

I see the wizard raises events but this would break the paradigm.

The command is defined:

    public ICommand NextStage
    {
        get
        {
            return _NextStage ?? (
                _NextStage = new RelayCommand(param => PrepNextStep(),
                                              param => Page((PageIndexes)CurrentStage).IsDirty
                                             ));

        }   //  get
    }   //  public ICommand NextStage

The XAML is:

    <xctk:Wizard    x:Name="wizMain"
                    Grid.Row="1"
                    FinishButtonClosesWindow="True" 
                    ItemsSource="{Binding wizardPages}" 
                    Background="White"
                    ExteriorPanelMinWidth="100"
                    HelpButtonVisibility="Hidden"
                    Next="{Binding Path=NextStage}"
                    >
    </xctk:Wizard>

The error that is thrown at runtime is:

'Provide value on 'System.Windows.Data.Binding' threw an exception.' Line number '33' and line position '25'.

Any help would be greatly appreciated.

TIA, Ray

Answer 1

Next is an event and not a dependency property that you can bind to an ICommand source property.

What you could do is to add a reference to System.Windows.Interactivity.dll and use an interaction trigger to invoke your command when the wizard raises the event:

<xctk:Wizard ... xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity">
    <i:Interaction.Triggers>
        <i:EventTrigger EventName="Next">
            <i:InvokeCommandAction Command="{Binding NextStage}" />
        </i:EventTrigger>
    </i:Interaction.Triggers>
</xctk:Wizard>