Question

I have a need of one DependencyProperty from a View in my ViewModel constructor:

My problem: MEF wouldn’t SatisfyImports() ‘because it is marked with one or more ExportAttributes’ (that is the exception)

This is the code structure for the VIEW:

public class MyView : UserControl
{
    [Export(MethodTypes.ChartType)]
    public Charts MyChartType
    {
        get
        {
            object k = GetValue(ChartTypeProperty);
            Charts f = (Charts)Enum.Parse(typeof(Charts), k.ToString(), true);
            return f;
        }
        set
        {
            SetValue(ChartTypeProperty, value);
        }
    }

    [Import(ViewModelTypes.GenericChartViewModel)]
    public object ViewModel
    {
        set
        {
            DataContext = value;
        }
    }

    public MyView()
    {
        InitializeComponent();

        if (!ViewModelBase.IsInDesignModeStatic)
        {
            // Use MEF To load the View Model
            CompositionInitializer.SatisfyImports(this);
        }
    }
}

and the VIEWMODEL:

[PartCreationPolicy(CreationPolicy.NonShared)]
[Export(ViewModelTypes.GenericChartViewModel)]
public class GenericChartViewModel
{
    [ImportingConstructor]
    public GenericChartViewModel([Import(MethodTypes.ChartType)] Charts forChartType)
    {
        string test = forChartType.ToString();
    }
}

Please give me any hints on this or maybe suggest a better solution for passing parameters through mef

In my case, I would need to pass only dependecyproperty’s for now…

Thanks

Answer 1

Your work around isn’t really good.. can’t you remove the export from ChartTypes and pass it manually to whoever wants it? I presume the viewmodel is only one insterested in it..