MVVM light and ViewModelLocator

Question

I can see that the constructor of the ViewModelLocator is executed first when my application starts, but how to make the constructors of my ViewModels run after that, because inside them I have a registering that I want to happen in the beggining of my app. The constructor of my CustomViewModel runs when I enter the View because of the binding. The binding is to a master class called CompositeViewModel that contains my viewModels.

CompositeViewModel:

class CompositeViewModel
{
    public static CustomViewModel          customViewModel          { get; set; }

    static CompositeViewModel()
    {
        customViewModel          = new CustomViewModel();
    }
}

Here is my ViewModelLocator

public ViewModelLocator()
{
    ServiceLocator.SetLocatorProvider(() => SimpleIoc.Default);

    SimpleIoc.Default.Register<CustomViewModel>();
    SimpleIoc.Default.Register<MainViewModel>();
}

public CustomViewModelTripTypeView
{
    get
    {
        return ServiceLocator.Current.GetInstance<CustomViewModel>();
    }
}

This is the code in my CustomViewModels constructor:

public CustomViewModel()
    {
        Messenger.Default.Register<ObservableCollection<MyType>>
        (
            this,
            (action) => ReceiveMessage(action)
        );
    }

    private void ReceiveMessage(ObservableCollection<MyType> action)
    {
        DispatcherHelper.CheckBeginInvokeOnUI(() =>
        {
            this.MyDataSource.Clear();

            foreach (MyTypet mt in action)
            {
                this.MyDataSource.Add(mt);
            }
        });
    }

Answer 1

There is an overloaded method for Register method with bool argument

SimpleIOC.Default.Register<MainViewModel>(true);

This statement will immediately create an instance of MainViewModel .