In Prism Silverlight5, I have a shell which is divided into two vertical regions(leftRegion,rightRegion) & there are 2 views in Module1 i.e. (View1,View2). In leftRegion I have a View1 loaded which has a button. I want to dynamically load View2 on rightRegion using ViewModel & MEF.ViewModel code is :
[Export(typeof(LeftViewViewModel))]
public class LeftViewViewModel:ViewModelBase,IViewModel
{
[Import]
public IRegionManager CullingRegion { get; set; }
[ImportingConstructor]
public LeftViewViewModel(LeftView view)
:base(view)
{
LoadCommand = new DelegateCommand(LoadControl,CanLoadControl);
}
private void LoadControl()
{
CullingRegion.RegisterViewWithRegion("RightRegion", typeof(RightView));
}
protected bool CanLoadControl()
{
return true;
}
public DelegateCommand LoadCommand { get; set; }
}
LeftView.xaml.cs is :
[Import]
public ViewModels.IViewModel ViewModel
{
get { return (IViewModel) DataContext; }
set { DataContext = value; }
}
IModule implementation is :
[ModuleExport(typeof(CullingModuleModule1))]
public class CullingModuleModule1:IModule
{
[Import]
public IRegionManager CullingRegion { get; set; }
public void Initialize()
{
CullingRegion.RegisterViewWithRegion("ShellContentRegion", typeof (Container));
CullingRegion.RegisterViewWithRegion("LeftRegion", typeof(LeftView));
}
}
First of,I think your ViewModel should not be referenced by a View.
You may need to review View Injection with MEF.
As I've seen in multiple posts :
[Export]
public class YourViewClassName : UserControl
{
public YourViewClassName()
{
}
[Import]
public ILeftViewModel
{
get { return (ILeftViewModel )DataContext; }
set { DataContext = value; }
}
}
[Export(typeof(LeftViewViewModel))]
public class LeftViewViewModel : ILeftViewModel //ILeftViewModel inherits from IViewModel
{
public LeftViewViewModel()
{
}
}
Inside Module Initializer :
CullingRegion.Regions[YourRegionName].Add(ServiceLocator.Current.GetInstance<YourViewClassName>());
Hope it helps
Related
I have this code that creates a ViewModel for the page. However in the Viewmodel I want to access the property correctButtonPressed but it's not available.
How can I access this?
public partial class PhrasesFrame : Frame
{
public int correctButtonPressed;
public PhrasesFrameViewModel vm = new PhrasesFrameViewModel();
public PhrasesFrame() {
InitializeComponent();
}
private string abc()
{
var a = correctButtonPressed;
}
}
public class PhrasesFrameViewModel : ObservableProperty
{
private ICommand bButtonClickedCommand;
public ICommand BButtonClickedCommand
{
get
{
return bButtonClickedCommand ??
(bButtonClickedCommand = new Command(() =>
{
// Next line gives an error "use expression body for accessors" "use expression body for properties.
correctButtonPressed = 123;
}));
}
}
}
Expose it as a property on the view model and have the view access it.
public partial class PhrasesFrame : Frame {
public PhrasesFrameViewModel vm = new PhrasesFrameViewModel();
public PhrasesFrame() {
InitializeComponent();
}
private string abc() {
//View can access correctButtonPressed via the view model.
var a = vm.correctButtonPressed;
}
}
public class PhrasesFrameViewModel : ObservableProperty {
public int correctButtonPressed;
private ICommand bButtonClickedCommand;
public ICommand BButtonClickedCommand {
get {
return bButtonClickedCommand ??
(bButtonClickedCommand = new Command(() => {
correctButtonPressed = 123;
}));
}
}
}
After updating to ABP v3.0.0, I started getting DbContext disposed exception when running parallel requests to repository that create new UnitOfWork like this:
using (var uow = _unitOfWorkManager.Begin(TransactionScopeOption.RequiresNew))
I looked in the source code and found some code in AsyncLocalCurrentUnitOfWorkProvider that I don't understand. When setting current uow, it sets property in wrapper:
private static readonly AsyncLocal<LocalUowWrapper> AsyncLocalUow = new AsyncLocal<LocalUowWrapper>();
private static void SetCurrentUow(IUnitOfWork value)
{
lock (AsyncLocalUow)
{
if (value == null)
{
if (AsyncLocalUow.Value == null)
{
return;
}
if (AsyncLocalUow.Value.UnitOfWork?.Outer == null)
{
AsyncLocalUow.Value.UnitOfWork = null;
AsyncLocalUow.Value = null;
return;
}
AsyncLocalUow.Value.UnitOfWork = AsyncLocalUow.Value.UnitOfWork.Outer;
}
else
{
if (AsyncLocalUow.Value?.UnitOfWork == null)
{
if (AsyncLocalUow.Value != null)
{
AsyncLocalUow.Value.UnitOfWork = value;
}
AsyncLocalUow.Value = new LocalUowWrapper(value);
return;
}
value.Outer = AsyncLocalUow.Value.UnitOfWork;
AsyncLocalUow.Value.UnitOfWork = value;
}
}
}
private class LocalUowWrapper
{
public IUnitOfWork UnitOfWork { get; set; }
public LocalUowWrapper(IUnitOfWork unitOfWork)
{
UnitOfWork = unitOfWork;
}
}
That does not look thread-safe, as any thread can set new UnitOfWork and then dispose it.
Is it a bug? I can use my own implementation of ICurrentUnitOfWorkProvider, without wrapping, but I'm not sure if that is correct.
Update
I can't give an example with DbContext disposed exception, but here is one with null reference exception in repository.GetAll() method. I think it has the same reason.
namespace TestParallelEFRequest
{
public class Ent1 : Entity<int> { public string Name { get; set; } }
public class Ent2 : Entity<int> { public string Name { get; set; } }
public class Ent3 : Entity<int> { public string Name { get; set; } }
public class Ent4 : Entity<int> { public string Name { get; set; } }
public class DomainStartEvent : EventData {}
public class DBContext : AbpDbContext {
public DBContext(): base("Default") {}
public IDbSet<Ent1> Ent1 { get; set; }
public IDbSet<Ent2> Ent2 { get; set; }
public IDbSet<Ent3> Ent3 { get; set; }
public IDbSet<Ent4> Ent4 { get; set; }
}
public class TestService : DomainService, IEventHandler<DomainStartEvent>
{
private readonly IRepository<Ent1> _rep1;
private readonly IRepository<Ent2> _rep2;
private readonly IRepository<Ent3> _rep3;
private readonly IRepository<Ent4> _rep4;
public TestService(IRepository<Ent1> rep1, IRepository<Ent2> rep2, IRepository<Ent3> rep3, IRepository<Ent4> rep4) {
_rep1 = rep1;_rep2 = rep2;_rep3 = rep3;_rep4 = rep4;
}
Task HandleEntityes<T>(IRepository<T> rep, int i) where T : class, IEntity<int> {
return Task.Run(() => {
using (var uow = UnitOfWorkManager.Begin(TransactionScopeOption.RequiresNew)) {
Thread.Sleep(i); // Simulating work
rep.GetAll(); // <- Exception here
}
});
}
public void HandleEvent(DomainStartEvent eventData) {
using (var uow = UnitOfWorkManager.Begin(TransactionScopeOption.RequiresNew)) {
var t1 = HandleEntityes(_rep1, 10);
var t2 = HandleEntityes(_rep2, 10);
var t3 = HandleEntityes(_rep3, 10);
var t4 = HandleEntityes(_rep4, 1000);
Task.WaitAll(t1, t2, t3, t4);
}
}
}
[DependsOn(typeof(AbpEntityFrameworkModule))]
public class ProgrammModule : AbpModule
{
public override void PreInitialize() { Configuration.DefaultNameOrConnectionString = "Default"; }
public override void Initialize()
{
IocManager.RegisterAssemblyByConvention(Assembly.GetExecutingAssembly());
Database.SetInitializer<DBContext>(null);
}
}
class Program {
static void Main(string[] args) {
using (var bootstrapper = AbpBootstrapper.Create<ProgrammModule>()) {
bootstrapper.Initialize();
bootstrapper.IocManager.Resolve<IEventBus>().Trigger(new DomainStartEvent());
Console.ReadKey();
}
}
}
}
ActionBase, ActionA, ActionB and ActionC are Entities (from a database). ActionA, ActionB and ActionC are derived type of ActionBase.
ActionB and ActionC implements ISpecialAction with a SpecialProperty.
ex :
public interface ISpecialAction
{
Guid SpecialProperty { get; }
}
public partial class ActionBase
{
public objectX OnePropertyBase { get; set; }
}
public partial class ActionA : ActionBase
{
public objectY OnePropertyA { get; set; }
}
public partial class ActionB:ActionBase,ISpecialAction
{
public objectZ OnePropertyB { get; set; }
public Guid SpecialProperty
{
get
{
return OnePropertyB.ID;
}
}
}
public partial class ActionC : ActionBase ,ISpecialAction
{
public objectW OnePropertyC { get; set; }
public Guid SpecialProperty
{
get
{
return OnePropertyC.ID;
}
}
}
My problem is that SpecialProperty is build from other Properties of the objects (ActionB or ActionC) and when the cast (to ISpecialAction) is done, OtherProperty and OtherProperty2 are null.
I tried :
GetActionBase().ToList().Where(x=>x is ISpecialAction && ((dynamic) x).SpecialProperty== p_SpecialProperty);
GetActionBase().ToList().Where(x=>x is ISpecialAction && ((ISpecialAction) x).SpecialProperty== p_SpecialProperty);
GetActionBase().ToList().OfType<ISpecialAction>().Where(x => x.SpecialProperty== p_SpecialProperty).Cast<ActionBase>();
return GetActionOnGoing().ToList().OfType<ICityAction>().Cast<ActionBase>().Where(x => ((dynamic)x).CityId == p_CityId);
remark : OfType<> doesn't works with an Interface in Linq to entities but is ok in Linq to object
How do I access my property interface without knowing the type of the object?
I might missed something but this is Ok with the code you provided :
public class objectX
{
}
public class objectY
{
}
public class objectZ
{
public Guid ID { get { return Guid.NewGuid();} }
}
public class objectW
{
public Guid ID { get { return new Guid(); } }
}
class Program
{
private static Guid p_SpecialProperty;
static void Main(string[] args)
{
var result = GetActionBase().ToList().Where(x => x is ISpecialAction && ((dynamic)x).SpecialProperty == p_SpecialProperty).FirstOrDefault();
var result1 = GetActionBase().ToList().Where(x => x is ISpecialAction && ((ISpecialAction)x).SpecialProperty == p_SpecialProperty).FirstOrDefault();
var result2 = GetActionBase().ToList().OfType<ISpecialAction>().Where(x => x.SpecialProperty == p_SpecialProperty).Cast<ActionBase>().FirstOrDefault();
}
private static IEnumerable<ActionBase> GetActionBase()
{
return new List<ActionBase> {new ActionA{OnePropertyA= new objectY()}, new ActionB{OnePropertyB=new objectZ()},new ActionC{OnePropertyC=new objectW()} };
}
}
Not sure if I exactly understand your question, but could you try using an intermediate interface, such as:
public interface ISpecialActionB : ISpecialAction
{
objectZ OnePropertyB { get; set; }
}
public class ActionB : ActionBase, ISpecialActionB
{
//same stuff
}
and casting to that instead.
var b = new ActionB{OnePropertyB = new Whatever()};
var bAsSpecial = b as ISpecialActionB;
var whatever = b.OnePropertyB; // should not be null
It' ok.
Your example run very well without problem so I searched in a other way : AutoMapper.
l_List.Actions = Mapper.Map<List<ActionBase>, Action[]>(l_ActionManagement.GetActionBySpecialId(l_Special.ID).ToList());
The problem was not interfaces or Linq queries but it was that automapper need an empty constructor and in this constructor, I need to initialize OnePropertyB and OnePropertyC to compute SpecialProperty.
Thanks
I tend to dislike posting dozens of lines of code and assuming the community at large is interested in untangling my mess. In this case I've exercised everything I can think to search on Google, traced through Glimpse, and Firebug/Fiddler, and what I'm left with is an occasionally working behavior, which is particularly annoying to debug. So, I'm calling out for help.
Here's the gist: I've got a series of classes that handle MVC routes that are otherwise not found (and would produce a 404 error) thanks to #AndrewDavey. I'm attempting to intercept the 404 and show data-driven content where any exists. It all works until I refresh the page. The request works on the first load, but it never fires again after that.
If you're bored or have an itch, the entire code block is below.
Setup goes like this:
Add WebActivator via NuGet
In your AppStart folder add a cs file with the code below
Add a "PageContext" connection string to your web.config
Run the app, the default MVC screen shows up
Now add "/abc" to the end of the url (i.e http://localhost/abc)
A cshtml view, stored in the database, will render.
Change the view's markup in the database and reload the page. Notice no change in your browser.
the /abc route assumes you have a record in the database with the following
Path: "~/abc/index.cshtml"
View: "#{ Layout = null;}<!doctype html><html><head><title>abc</title></head><body><h2>About</h2></body></html>"
I've got no idea why the first request works and subsequent requests don't hit break points and serve up stale content.
My suspicions are:
Some voodoo with the VirtualFile
Something cached (but where?)
A misconfigured handler
Thanks for the help - here's the code (as I shamefully tuck my tail for posting this much code).
using System;
using System.Collections;
using System.Collections.Generic;
using System.Data.Entity;
using System.IO;
using System.Linq;
using System.Text;
using System.Web;
using System.Web.Caching;
using System.Web.Hosting;
using System.Web.Mvc;
using System.Web.Routing;
using System.Web.SessionState;
using Microsoft.Web.Infrastructure.DynamicModuleHelper;
using SomeCms;
[assembly: WebActivator.PreApplicationStartMethod(typeof(Sample.Web.App_Start.cms), "PreStart")]
namespace Sample.Web.App_Start
{
public static class cms
{
public static void PreStart()
{
DynamicModuleUtility.RegisterModule(typeof(InstallerModule));
}
}
}
namespace SomeCms
{
class ActionInvokerWrapper : IActionInvoker
{
readonly IActionInvoker actionInvoker;
public ActionInvokerWrapper(IActionInvoker actionInvoker)
{
this.actionInvoker = actionInvoker;
}
public bool InvokeAction(ControllerContext controllerContext, string actionName)
{
if (actionInvoker.InvokeAction(controllerContext, actionName))
{
return true;
}
// No action method was found.
var controller = new CmsContentController();
controller.ExecuteCmsContent(controllerContext.RequestContext);
return true;
}
}
class ControllerFactoryWrapper : IControllerFactory
{
readonly IControllerFactory factory;
public ControllerFactoryWrapper(IControllerFactory factory)
{
this.factory = factory;
}
public IController CreateController(RequestContext requestContext, string controllerName)
{
try
{
var controller = factory.CreateController(requestContext, controllerName);
WrapControllerActionInvoker(controller);
return controller;
}
catch (HttpException ex)
{
if (ex.GetHttpCode() == 404)
{
return new CmsContentController();
}
throw;
}
}
static void WrapControllerActionInvoker(IController controller)
{
var controllerWithInvoker = controller as Controller;
if (controllerWithInvoker != null)
{
controllerWithInvoker.ActionInvoker = new ActionInvokerWrapper(controllerWithInvoker.ActionInvoker);
}
}
public SessionStateBehavior GetControllerSessionBehavior(RequestContext requestContext, string controllerName)
{
return factory.GetControllerSessionBehavior(requestContext, controllerName);
}
public void ReleaseController(IController controller)
{
factory.ReleaseController(controller);
}
}
class InstallerModule : IHttpModule
{
static bool installed;
static readonly object installerLock = new object();
public void Init(HttpApplication application)
{
if (installed)
{
return;
}
lock (installerLock)
{
if (installed)
{
return;
}
Install();
installed = true;
}
}
static void Install()
{
Database.SetInitializer(new CreateDatabaseIfNotExists<PageContext>());
HostingEnvironment.RegisterVirtualPathProvider(new ExampleVirtualPathProvider());
WrapControllerBuilder();
AddNotFoundRoute();
AddCatchAllRoute();
}
static void WrapControllerBuilder()
{
ControllerBuilder.Current.SetControllerFactory(new ControllerFactoryWrapper(ControllerBuilder.Current.GetControllerFactory()));
}
static void AddNotFoundRoute()
{
// To allow IIS to execute "/cmscontent" when requesting something which is disallowed,
// such as /bin or /add_data.
RouteTable.Routes.MapRoute(
"CmsContent",
"cmscontent",
new { controller = "CmsContent", action = "CmsContent" }
);
}
static void AddCatchAllRoute()
{
RouteTable.Routes.MapRoute(
"CmsContent-Catch-All",
"{*any}",
new { controller = "CmsContent", action = "CmsContent" }
);
}
public void Dispose() { }
}
public class CmsContentController : IController
{
public void Execute(RequestContext requestContext)
{
ExecuteCmsContent(requestContext);
}
public void ExecuteCmsContent(RequestContext requestContext)
{
//new CmsContentViewResult().ExecuteResult(new ControllerContext(requestContext, new FakeController()));
new CmsContentViewResult().ExecuteResult(new ControllerContext(requestContext, new FakeController()));
}
// ControllerContext requires an object that derives from ControllerBase.
// NotFoundController does not do this.
// So the easiest workaround is this FakeController.
class FakeController : Controller { }
}
public class CmsContentHandler : IHttpHandler
{
public void ProcessRequest(HttpContext context)
{
var routeData = new RouteData();
routeData.Values.Add("controller", "CmsContent");
var controllerContext = new ControllerContext(new HttpContextWrapper(context), routeData, new FakeController());
var cmsContentViewResult = new CmsContentViewResult();
cmsContentViewResult.ExecuteResult(controllerContext);
}
public bool IsReusable
{
get { return false; }
}
// ControllerContext requires an object that derives from ControllerBase.
class FakeController : Controller { }
}
public class CmsContentViewResult : ViewResult
{
public CmsContentViewResult()
{
ViewName = "index";
}
public override void ExecuteResult(ControllerContext context)
{
var request = context.HttpContext.Request;
if (request != null && request.Url != null)
{
var url = request.Url.OriginalString;
ViewData["RequestedUrl"] = url;
ViewData["ReferrerUrl"] = (request.UrlReferrer != null && request.UrlReferrer.OriginalString != url)
? request.UrlReferrer.OriginalString
: null;
}
base.ExecuteResult(context);
}
}
public class ExampleVirtualPathProvider : VirtualPathProvider
{
private readonly List<SimpleVirtualFile> virtualFiles = new List<SimpleVirtualFile>();
public ExampleVirtualPathProvider()
{
var context = new PageContext();
var pages = context.Pages.ToList();
foreach (var page in pages)
{
virtualFiles.Add(new SimpleVirtualFile(page.Path));
}
}
public override bool FileExists(string virtualPath)
{
var files = (from f in virtualFiles
where f.VirtualPath.Equals(virtualPath, StringComparison.InvariantCultureIgnoreCase) ||
f.RelativePath.Equals(virtualPath, StringComparison.InvariantCultureIgnoreCase)
select f)
.ToList();
return files.Count > 0 || base.FileExists(virtualPath);
}
private class SimpleVirtualFile : VirtualFile
{
public SimpleVirtualFile(string filename) : base(filename)
{
RelativePath = filename;
}
public override Stream Open()
{
var context = new PageContext();
var page = context.Pages.FirstOrDefault(p => p.Path == RelativePath);
return new MemoryStream(Encoding.ASCII.GetBytes(page.View), false);
}
public string RelativePath { get; private set; }
}
private class SimpleVirtualDirectory : VirtualDirectory
{
public SimpleVirtualDirectory(string virtualPath)
: base(virtualPath)
{
}
public override IEnumerable Directories
{
get { return null; }
}
public override IEnumerable Files
{
get
{
return null;
}
}
public override IEnumerable Children
{
get { return null; }
}
}
public override VirtualFile GetFile(string virtualPath)
{
var files = (from f in virtualFiles
where f.VirtualPath.Equals(virtualPath, StringComparison.InvariantCultureIgnoreCase) ||
f.RelativePath.Equals(virtualPath, StringComparison.InvariantCultureIgnoreCase)
select f).ToList();
return files.Count > 0
? files[0]
: base.GetFile(virtualPath);
}
public override CacheDependency GetCacheDependency(string virtualPath, IEnumerable virtualPathDependencies, DateTime utcStart)
{
return IsPathVirtual(virtualPath) ? null : base.GetCacheDependency(virtualPath, virtualPathDependencies, utcStart);
}
private bool IsPathVirtual(string virtualPath)
{
var checkPath = VirtualPathUtility.ToAppRelative(virtualPath);
return
virtualFiles.Any(f => checkPath.StartsWith(virtualPath, StringComparison.InvariantCultureIgnoreCase)) ||
virtualFiles.Any(f => checkPath.Replace("~", "").StartsWith(virtualPath, StringComparison.InvariantCultureIgnoreCase));
}
public override bool DirectoryExists(string virtualDir)
{
return IsPathVirtual(virtualDir) || Previous.DirectoryExists(virtualDir);
}
public override VirtualDirectory GetDirectory(string virtualDir)
{
return IsPathVirtual(virtualDir)
? new SimpleVirtualDirectory(virtualDir)
: Previous.GetDirectory(virtualDir);
}
}
public class ContentPage
{
public int Id { get; set; }
public string Path { get; set; }
public string View { get; set; }
}
public class PageContext : DbContext
{
public DbSet<ContentPage> Pages { get; set; }
}
}
This question turns out to be a non-issue. My oversight of the cache dependency in the virtual path provider is returning null for virtual paths. As such, the view is cached indefinitely.
The solution is to use a custom cache dependency provider that expires immediately.
public class NoCacheDependency : CacheDependency
{
public NoCacheDependency()
{
NotifyDependencyChanged(this, EventArgs.Empty);
}
}
public override CacheDependency GetCacheDependency(string virtualPath, IEnumerable virtualPathDependencies, DateTime utcStart)
{
return IsPathVirtual(virtualPath) ? new NoCacheDependency() : base.GetCacheDependency(virtualPath, virtualPathDependencies, utcStart);
}
Using MVVM Light, I'm trying to develop a rather simple WP7 application. I've run into a problem using the navigation service. I can navigate to a page, but after pressing the back button I can't navigate to the same page again. NavigationService throws a NullReferenceException.
I have implemented my navigation using Messaging from the GalaSoft.MvvmLight.Messaging namespace. All my views inherits from a customized PhoneApplicationPage base class that registrers a listener on "NavigationRequest":
public class PhoneApplicationPage : Microsoft.Phone.Controls.PhoneApplicationPage
{
public PhoneApplicationPage() : base()
{
Messenger.Default.Register<Uri>(this, "NavigationRequest", (uri) => NavigationService.Navigate(uri));
}
}
From my view models I post Uri's to this listener:
SendNavigationRequestMessage(new Uri("/View/AppSettingsView.xaml", UriKind.Relative));
Like i said, this works except when navigating after pressing the Back button.
Why is this and how can I solve it?
Is there a better way to implement navigation using MVVM Light?
I'm using MVVM Light as well. I have a class called PageConductor, which is based on what John Papa (Silverlight MVP) from Microsoft uses. Here's the PageConductor Service I use
public class PageConductor : IPageConductor
{
protected Frame RootFrame { get; set; }
public PageConductor()
{
Messenger.Default.Register<Messages.FrameMessage>(this, OnReceiveFrameMessage);
}
public void DisplayError(string origin, Exception e, string details)
{
string description = string.Format("Error occured in {0}. {1} {2}", origin, details, e.Message);
var error = new Model.Error() { Description = description, Title = "Error Occurred" };
Messenger.Default.Send(new Messages.ErrorMessage() { Error = error });
}
public void DisplayError(string origin, Exception e)
{
DisplayError(origin, e, string.Empty);
}
private void OnReceiveFrameMessage(Messages.FrameMessage msg)
{
RootFrame = msg.RootFrame;
}
private void Go(string path, string sender)
{
RootFrame.Navigate(new Uri(path, UriKind.Relative));
}
public void GoBack()
{
RootFrame.GoBack();
}
}
In my MainPage.xaml.cs constructor, I have this, which creates an instance of my ContentFrame in my PageConductor service.:
Messenger.Default.Send(new Messages.FrameMessage() { RootFrame = ContentFrame });
I then use dependency injection to instantiate an instance of my PageConductor Service into my MainPage ViewModel. Here is my MainViewModel class:
protected Services.IPageConductor PageConductor { get; set; }
public RelayCommand<string> NavigateCommand { get; set; }
public MainViewModel(Services.IPageConductor pageConductor)
{
PageConductor = pageConductor;
RegisterCommands();
}
private void RegisterCommands()
{
NavigateCommand = new RelayCommand<string>(
(source) => OnNavigate(source));
}
private void OnNavigate(string sender)
{
PageConductor.GoToView(sender, "main");
}
Notice the instance of my PageConductorService as a parameter in my MainViewModel constructor method. I pass this in via my ViewModelLocator:
private readonly TSMVVM.Services.ServiceProviderBase _sp;
public ViewModelLocator()
{
_sp = Services.ServiceProviderBase.Instance;
CreateMain(_sp);
}
#region MainPageViewModel
public static MainViewModel MainStatic
{
get
{
Services.ServiceProviderBase SP = Services.ServiceProviderBase.Instance;
if (_main == null)
{
CreateMain(SP);
}
return _main;
}
}
[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Performance",
"CA1822:MarkMembersAsStatic",
Justification = "This non-static member is needed for data binding purposes.")]
public MainViewModel Main
{
get
{
return MainStatic;
}
}
public static void ClearMain()
{
_main.Cleanup();
_main = null;
}
public static void CreateMain(Services.ServiceProviderBase SP)
{
if (_main == null)
{
_main = new MainViewModel(SP.PageConductor);
}
}
#endregion
For further reference, my Messages.FrameMessage class is simply:
internal class FrameMessage
{
public Frame RootFrame { get; set; }
}
I've had no issues with forward/back buttons.