How to add PRISM modules to Toolbar using MEF and MVVM

Question

I am using PRISM 4.0 with MEF as my container. I have defined 2 regions, ToolBar and MainRegion in my Shell. The toolbar region is automatically populated with my ToolBarModule using a custom RegionBehaviour - AutoPopulateExportedViewsBehaviour. My MainRegion can contain 1 or more View modules which will be docked via a third party dock layout manager.

I'm having trouble creating the toolbar buttons to represent the available views in my application. My idea was to use a ToolBarService or an Event pattern so that each View module could register itself with the ToolBar in a decoupled manner.

However it seems my View Module contructor is not called until I call RegionManager.RegisterViewWithRegion...

How can I control the initialisation of my modules so they can register with the ToolBar. Thus allowing them to add a button but not actually show the view itself. The View will only be shown when the button the view just registered is clicked.

Thanks

Answer 1

How can I control the initialisation of my modules so they can register with the ToolBar but not be shown initally?

I'm not sure what you mean by that.

I understand that you want modules to register it's own navigation part when they loaded. I have similar scenario where I have menu bar on top and button bar below. Each module when loaded - inserts it's own buttons/menus using Initialize code:

public void Initialize()
        {
            this.RegionManager.RegisterViewWithRegion(RegionNames.Menu, typeof(NavigationView));
            this.RegionManager.RegisterViewWithRegion(RegionNames.Toolbar, typeof(ToolbarNavigationView));
        }

Those regions have actual buttons/items which when pressed call something else. For examle, here is NavigationViewModel

namespace IDATT.Module.SystemManager.ViewModels
{
    using System;
    using System.ComponentModel.Composition;

    using Microsoft.Practices.Prism.Regions;

    [Export]
    public class NavigationViewModel
    {
        [Import]
        public ISecurityService SecurityService { get; set; }

        [Import]
        public IRegionManager RegionManager { get; set; }

        public void Mail()
        {
            this.RegionManager.RequestNavigate(RegionNames.Tabs, new Uri(typeof(MailView).Name, UriKind.Relative));
        }

        public void MaintainUser()
        {
            this.RegionManager.RequestNavigate(RegionNames.Tabs, new Uri(typeof(MaintainUserView).Name, UriKind.Relative));
        }

        public void MaintainGroup()
        {
            this.RegionManager.RequestNavigate(RegionNames.Tabs, new Uri(typeof(MaintainGroupView).Name, UriKind.Relative));
        }

        public void MaintainMailTemplate()
        {
            this.RegionManager.RequestNavigate(RegionNames.Tabs, new Uri(typeof(MaintainMailTemplateView).Name, UriKind.Relative));
        }

        public void SetUpOptions()
        {
            this.RegionManager.RequestNavigate(RegionNames.Tabs, new Uri(typeof(SetUpSystemManagerOptionsView).Name, UriKind.Relative));
        }

        public void Logout()
        {
            this.SecurityService.Logout();
        }
    }
}

Answer 2

It looks like I can "force" the constructor of my view module to be called by using a custom RegionBehaviour. Inside of this I can cast my view module to a specific base view or interface type and call the a function. This will then register my view with the toolbar but not necessarily show the view in the "main" region of my application.

Thanks for your help.