Popup window in Silverlight 4 and Prism

In Silverlight and PRISM, what is the good way to open a popup child 开发者_运维知识库window which is in one Module by passing a parameter from a ViewModel in different Module.

Create a common interface/class known to both module, called IChildWindowService, register the IChildWindowServe/ChildWindowService in the bootstrapper.

//Highly simplified version
//Can be improved by window reuse, parameter options, stronger eventing
public class ChildWindowService : IChildWindowService
{
    public ChildWindowService(IServiceLocator container)
    {
        _container = container;
    } 
    public void Show<TViewModel>(TViewModel viewModel = null, Action<TViewModel, bool?> callBack = null) where TViewModel is IViewModel
    {
        var viewName = typeof(TViewModel).Name.Replace("Model", string.Empty);
        // In bootstrapper register all instances of IView or register each view one by one
        var view = _container.GetInstance<IView>(viewName);
        viewModel = viewModel ?? _container.GetInstance<TViewModel>();
        view.DataContext = viewModel;
        var window = new ChildWindow();
        window.Content = view;
        var handler = (s,e) => { window.Close(); }
        viewModel.RequestClose += handler; 
        view.Closed += (s,e) => { viewModel.RequestClose -= handler; }
        // In silverlight all windows show as Modal, if you are using a third party you can make a decision here
        window.Show();
    }
}

Create a common CompositePresentationEvent, this event will pass the parameters from point a to point b

public class OpenChildWindowWithParameters : CompositePresentationEvent<ParamEventArgs>{}

The ViewModel in Module A raises the Event. The Controller in Module B registers and reacts to the Event. The Controller in Module B takes the child window service as a dependency. When the event is raised the Controller will create the VM in Module B and pass the parameters to it, from the event, it will also use the Service to display a ChildWindow.