When I call `ShowRevertInventorySignDialogView()` through COMMAND, event throws ObjectNullException. I'm thinking that Object is not dispose as its assined to `CurrentViewModel` property.

Both `GetReport()` and `ShowRevertInventorySignDialogView()` functions called by Command which are binded to Buttons. I'm pretty sure that `GetReport()` function is called first so that object is created before raising the event.

What am I missing here?

```
class MainWindowViewModel : ViewModel{

    public ViewModel CurrentViewModel
    {
        get { return currentViewModel; }
        set { currentViewModel = value; NotifyPropertyChanged(); }
    }

    public void GetReport()
    {
        inventoryReportViewModel = new InventoryReportViewModel();
        inventoryReportViewModel.OnStatusChange += Event_OnStatusChange;
        CurrentViewModel = inventoryReportViewModel;          
    }
}

public class InventoryReportViewModel : InventoryBaseViewModel
{
    public event EventHandler<StatusChangeEventArgs> OnStatusChange;

    private void ShowRevertInventorySignDialogView()
    {
        OnStatusChange(this, new StatusChangeEventArgs("test",10));
        ....
        ....
    }
}

```

XAML;

```
<ContentControl Content="{Binding Path=CurrentViewModel}" Margin="20 10 20 0"></ContentControl>

```