I was trying to use Unity 2.0 beta 2 for Silverlight in my Windows Phone 7 project and I kept getting this crash:
Microsoft.Practices.Unity.Silverlight.dll!Microsoft.Practices.ObjectBuilder2.DynamicMethodConstructorStrategy.DynamicMethodConstructorStrategy() + 0x1f bytes
Microsoft.Practices.Unity.Silverlight.dll!Microsoft.Practices.ObjectBuilder2.DynamicMethodConstructorStrategy.DynamicMethodConstructorStrategy() + 0x1f bytes mscorlib.dll!System.Reflection.RuntimeConstructorInfo.InternalInvoke(System.Reflection.RuntimeConstructorInfo rtci = {System.Reflection.RuntimeConstructorInfo}, System.Reflection.BindingFlags invokeAttr = Default, System.Reflection.Binder binder = null, object parameters = {object[0]}, System.Globalization.CultureInfo culture = null, bool isBinderDefault = false, System.Reflection.Assembly caller = null, bool verifyAccess = true, ref System.Threading.StackCrawlMark stackMark = LookForMyCaller)
mscorlib.dll!System.Reflection.RuntimeConstructorInfo.InternalInvoke(object obj = null, System.Reflection.BindingFlags invokeAttr = Default, System.Reflection.Binder binder = null, object[] parameters = {object[0]}, System.Globalization.CultureInfo culture = null, ref System.Threading.StackCrawlMark stackMark = LookForMyCaller) + 0x103 bytes
mscorlib.dll!System.Activator.InternalCreateInstance(System.Type type = {Name = "DynamicMethodConstructorStrategy" FullName = "Microsoft.Practices.ObjectBuilder2.DynamicMethodConstructorStrategy"}, bool nonPublic = false, ref System.Threading.StackCrawlMark stackMark = LookForMyCaller) + 0xf0 bytes mscorlib.dll!System.Activator.CreateInstance() + 0xc bytes
Microsoft.Practices.Unity.Silverlight.dll!Microsoft.Practices.ObjectBuilder2.StagedStrategyChain.AddNew(Microsoft.Practices.Unity.ObjectBuilder.UnityBuildStage stage = Creation) + 0x1d bytes
Microsoft.Practices.Unity.Silverlight.dll!Microsoft.Practices.Unity.UnityDefaultStrategiesExtension.Initialize() + 0x6c bytes
Microsoft.Practices.Unity.Silverlight.dll!Microsoft.Practices.Unity.UnityContainerExtension.InitializeExtension(Microsoft.Practices.Unity.ExtensionContext context = {Microsoft.Practices.Unity.UnityContainer.ExtensionContextImpl}) + 0x31 bytes
Microsoft.Practices.Unity.Silverlight.dll!Microsoft.Practices.Unity.UnityContainer.AddExtension(Microsoft.Practices.Unity.UnityContainerExtension extension = {Microsoft.Practices.Unity.UnityDefaultStrategiesExtension}) + 0x1a bytes
Microsoft.Practices.Unity.Silverlight.dll!Microsoft.Practices.Unity.UnityContainer.UnityContainer() + 0xf bytes
Thinking I could resolve it I've tried a few things but to no avail.
Turns out that this is a rather fundamental problem and my assumption that Windows Phone 7 is Silverlight 3 + Some other stuff is wrong. This page describes the differences between Mobile Silverlight and Silverlight 3.
Of particular interest is this:
The System.Reflection.Emit namespace is not supported in Silverlight for Windows Phone.
This is precisely why Unity is crashing on the phone, DynamicMethodConstructorStrategy class uses System.Reflection.Emit quite extensively...
So the question is, what alternative to Unity is there for Windows Phone 7?
So, in the spirit of answering my own questions, I've put together a simple DI container (using Activator.CreateInstance for instantiating things). All this does is support type registrations and instance registrations.
Seems to be doing the job. Will worry about performance later.
public class DuplicateRegistrationException : Exception {
public DuplicateRegistrationException() { }
public DuplicateRegistrationException(string message) : base(message) { }
public DuplicateRegistrationException(string message, Exception inner) : base(message, inner) { }
}
public interface IDIContainer {
void Register<TIntf, TClass> () where TIntf: class where TClass : TIntf;
TIntf Resolve<TIntf>() where TIntf : class;
void RegisterInstance<TIntf>(TIntf instance);
}
public class DIContainer : IDIContainer{
Dictionary<Type, Type> m_TypeRegistrations;
Dictionary<Type, object> m_InstanceRegistrations;
public DIContainer() {
m_TypeRegistrations = new Dictionary<Type, Type>();
m_InstanceRegistrations = new Dictionary<Type, object>();
}
#region IDIContainer Members
public void Register<TIntf, TClass>()
where TIntf : class
where TClass : TIntf {
if(DoesRegistrationExist<TIntf>())
throw new DuplicateRegistrationException("Can only contain one registration per type");
m_TypeRegistrations.Add(typeof(TIntf), typeof(TClass));
}
public TIntf Resolve<TIntf>() where TIntf : class {
return Resolve(typeof(TIntf)) as TIntf;
}
private object Resolve(Type type) {
if(!m_TypeRegistrations.ContainsKey(type)) {
if(!m_InstanceRegistrations.ContainsKey(type))
throw new NotSupportedException("Cannot find registration for type " + type.FullName + ".");
else
return m_InstanceRegistrations[type];
} else {
var createdType = m_TypeRegistrations[type];
ConstructorInfo[] constructors = createdType.GetConstructors();
ConstructorInfo mostSpecificConstructor = null;
foreach(var c in constructors) {
if(mostSpecificConstructor == null || mostSpecificConstructor.GetParameters().Length < c.GetParameters().Length) {
mostSpecificConstructor = c;
}
}
List<object> constructorParameters = new List<object>();
foreach(var a in mostSpecificConstructor.GetParameters()) {
constructorParameters.Add(Resolve(a.ParameterType));
}
return Activator.CreateInstance(createdType, constructorParameters.ToArray());
}
}
private bool DoesRegistrationExist<T>() {
return m_InstanceRegistrations.ContainsKey(typeof(T)) || m_TypeRegistrations.ContainsKey(typeof(T));
}
public void RegisterInstance<TIntf>(TIntf instance) {
if(DoesRegistrationExist<TIntf>()) {
throw new DuplicateRegistrationException("Can only contain one registration per type");
}
m_InstanceRegistrations.Add(typeof(TIntf), instance);
}
#endregion
Funq has been in development for over a year and now has a 1.0 release. It's designed to be fast and run under Compact Framework and Windows Phone 7. Another big advantage is that the author has done great a screencast series explaining its development process using TDD which is very informative!
As an aside, the most recent performance tests that I can find are from March 2009 showing it beating the pants off Unity, Autofac, Ninject, and StructureMap. I'm trying to locate more recent tests and will update this post if I do.
If you cannot find an IOC container that works on Windows Phone 7 (and I wouldn't be surprised you cannot) then I'd suggest going with a different DI strategy.
I just started putting together a Windows Phone 7 Extension Tools project on codeplex. The current version checked in supports IoC with implicit DI along with the Common Service Locator to allow complete abstraction of your code and the container they use.
Check it out over at:
http://wp7.codeplex.com
Cheers,
Simon Hart
The OpenNETCF.IoC framework works on Windows desktop, Mono, Windows Mobile, Windows Phone 7 and MonoTouch. I'm a fan of code reuse.
It's modelled after the SCSF/CAB (in object model, not crappy perf), so many of those tutorials are valid and you can leverage existing knowledge and code assets.
Despite Mark Seeman says "the world doesn’t need yet another container" in his excellent book "Dependency Injection in .NET", I decided to implement my own DI container for WP7 which provides the major DI features:
object composition
lifetime management
interception which allows you to aspect-oriented programming approaches
The container is the part of PhoneCore Framework, which you can find here:
http://phonecore.codeplex.com
Related
PLEASE READ THE EDIT SECTION, IT CAN HELP ME TO CLARIFY THE QUESTION
I have this structure right now:
WebApp.csproj
Application.csproj
Data.csproj
Oracle.csproj
SqlServer.csproj
My Data (3) is just a project referenced by WebApp (1) to decides which one (4 or 5) should be called based on the web.config.
If the web.config contains the app.key DBaseDL with 'oracle' value, it should LoadAssembly 4, instead, assembly 5.
Classes of 4 and 5 are mirror but with the query on each syntax (4 has syntax for oracle and 5 for sql server). Those mirror classes implements a commom interface between then, like this:
namespace MyProject.Oracle
{
public class User : IUser
{
//...
}
}
namespace MyProject.SqlServer
{
public class User : IUser
{
//...
}
}
On Data (3) csproj I'm trying to create a Factory which creates the User class from 4 or 5, based on the web.config settings like I said before. So I do something like this:
public class UserDataFactory : IDataLayerFactory<IUser>
{
private readonly string _key;
public UserDataFactory(string key)
{
_key = key;
}
public IUser Create()
{
string strPath = string.Empty;
string strClassName = string.Empty;
string strAssemblyName = string.Empty;
string strVersion = Assembly.GetExecutingAssembly().GetName().Version.ToString();
if (_key.Equals("oracle"))
strAssemblyName = "MyProjejct.Oracle";
else
strAssemblyName = "MyProject.SQLServer";
strPath = strAssemblyName + ", Version=" + strVersion + ", Culture=neutral, PublicKeyToken=xxxxxxx";
strClassName = strAssemblyName + ".User";
return (IUser)Assembly.Load(strPath).CreateInstance(strClassName);
}
}
My problem starts on this IDataFactory class.
I already did everything works with forced values (like always on SQLServer or Oracle) but not with IoC + the settings key for database.
I'm trying to do something like this with AutoFac but I'm probably missing something and I'm blind.
public static void ConfigureContainer()
{
var builder = new ContainerBuilder();
builder.RegisterControllers(Assembly.GetExecutingAssembly()).InstancePerRequest();
builder.RegisterType<Mediator>().As<IMediator>().InstancePerLifetimeScope();
builder.RegisterType<AutofacValidatorFactory>().As<IValidatorFactory>().SingleInstance();
builder.RegisterType<AutofacDataLayerFactory>().As<IDataFactory>().InstancePerLifetimeScope();
builder.RegisterType<FluentValidationModelValidatorProvider>().As<ModelValidatorProvider>();
builder.RegisterType<RegistryManagerService>().As<IRegistryManagerService>().SingleInstance().WithParameter("appName", ConfigurationManager.AppSettings["APPNAME"]);
builder.Register<ServiceFactory>(context =>
{
var c = context.Resolve<IComponentContext>();
return t => c.Resolve(t);
});
builder.RegisterAssemblyTypes(Assembly.Load("MyProj.Application"))
.Where(x => x.Name.EndsWith("Handler"))
.AsImplementedInterfaces();
builder.RegisterAssemblyTypes(Assembly.Load("MyProj.Application"))
.Where(x => x.Name.EndsWith("Validator"))
.AsImplementedInterfaces()
.InstancePerLifetimeScope();
builder.RegisterAssemblyTypes(Assembly.Load("MyProj.Application"))
.Where(x => x.Name.EndsWith("DataFactory"))
.AsImplementedInterfaces()
.InstancePerLifetimeScope();
var container = builder.Build();
DependencyResolver.SetResolver(new AutofacDependencyResolver(container));
}
}
Just to say, IDataFactory is about User now, but it will be a lot of things, and I don't want to register for every class again on autofac. I'm trying to register all my IDataFactory so the constructor of my handlers on Application.csproj should get the already created by factory classes, the DataAccess object from Oracle or SqlServer.
Can someone help me?
EDIT
After digging and learning a little more about the AutoFac, IoC and DI, I realize a easy way to register my class, but I'm pretty sure there is a better and more ellegant solution then mine.
I just read the key from configuration manager and write this code at the AutoFacConfig file:
if (key == "oracle")
builder.RegisterType<DocspiderOracleDbService>().As<IDocspiderDbService>().InstancePerRequest();
else
builder.RegisterType<DocspiderSqlServerDbService>().As<IDocspiderDbService>().InstancePerRequest();
This worked because only the service from the correct database is registered, but, I'll keep digging how to make it the right away.
If anyone have an idea, I'll be greatfull.
I have spent over two weeks searching google, bing, stack overflow, and msdn docs trying to figure out how to do a proper dependency injection for a mobile app that I am developing. To be clear, I do DI every day in web apps. I do not need a crash course on what, who, and why DI is important. I know it is, and am always embracing it.
What I need to understand is how this works in a mobile app world, and in particular a UWP Template 10 Mobile app.
From my past, in a .net/Asp app I can "RegisterType(new XYZ).Singleton() blah" {please forgive syntax; just an example} in App_Start.ConfigureServices. This works almost identical in .netcore, granted some syntactic changes.
My problem is now I am trying to provide my api is going to an UWP app that needs to digest my IXYZ service. By no means do I think that they should "new" up an instance every time. There has to be a way to inject this into a container on the UWP side; and I feel I am missing something very simple in the process.
Here is the code I have:
App.xaml.cs
public override async Task OnStartAsync(StartKind startKind, IActivatedEventArgs args)
{
// TODO: add your long-running task here
//if (args.Kind == ActivationKind.LockScreen)
//{
//}
RegisterServices();
await NavigationService.NavigateAsync(typeof(Views.SearchCompanyPage));
}
public static IServiceProvider Container { get; private set; }
private static void RegisterServices()
{
var services = new ServiceCollection();
services.AddSingleton<IXYZ, XYZ>();
Container = services.BuildServiceProvider();
}
MainPage.xaml.cs:
public MainPage()
{
InitializeComponent();
NavigationCacheMode = NavigationCacheMode.Enabled;
}
MainPageViewModel:
public class MainPageViewModel : ViewModelBase
{
private readonly IXYZ _xyz;
public MainPageViewModel(IXYZ xyz)
{
//Stuff
_xyz= xyz;
}
}
I now get the error:
XAML MainPage...ViewModel type cannot be constructed. In order to be constructed in XAML, a type cannot be abstract, interface nested generic or a struct, and must have a public default constructor.
I am willing to use any brand of IoC Container, but what I need is an example of how to properly use DI for services in a UWP app. 99.9% of questions about DI is about Views (i.e. Prism?) not just a simple DI for a service (i.e. DataRepo; aka API/DataService).
Again, I feel I am missing something obvious and need a nudge in the right direction. Can somebody show me an example project, basic code, or a base flogging on how I should not be a programmer...please don't do that (I don't know if my ego could take it).
You can try to Microsoft.Hosting.Extensions just like ASP.NET, there's an implementation on Xamarin.Forms by James Montemagno, as well it can be used in UWP I have tried and it works perfectly. You have to change some parts in order to get it working.
In OnLaunched Method add Startup.Init();
public static class Startup
{
public static IServiceProvider ServiceProvider { get; set; }
public static void Init()
{
StorageFolder LocalFolder = ApplicationData.Current.LocalFolder;
var configFile = ExtractResource("Sales.Client.appsettings.json", LocalFolder.Path);
var host = new HostBuilder()
.ConfigureHostConfiguration(c =>
{
// Tell the host configuration where to file the file (this is required for Xamarin apps)
c.AddCommandLine(new string[] { $"ContentRoot={LocalFolder.Path}" });
//read in the configuration file!
c.AddJsonFile(configFile);
})
.ConfigureServices((c, x) =>
{
// Configure our local services and access the host configuration
ConfigureServices(c, x);
}).
ConfigureLogging(l => l.AddConsole(o =>
{
//setup a console logger and disable colors since they don't have any colors in VS
o.DisableColors = true;
}))
.Build();
//Save our service provider so we can use it later.
ServiceProvider = host.Services;
}
static void ConfigureServices(HostBuilderContext ctx, IServiceCollection services)
{
//ViewModels
services.AddTransient<HomeViewModel>();
services.AddTransient<MainPageViewModel>();
}
static string ExtractResource(string filename, string location)
{
var a = Assembly.GetExecutingAssembly();
using (var resFilestream = a.GetManifestResourceStream(filename))
{
if (resFilestream != null)
{
var full = Path.Combine(location, filename);
using (var stream = File.Create(full))
{
resFilestream.CopyTo(stream);
}
}
}
return Path.Combine(location, filename);
}
}
Injecting a ViewModel is possible as well which is pretty nice.
With help from #mvermef and the SO question Dependency Injection using Template 10 I found a solutions. This turned out to be a rabbit hole where at every turn I ran into an issue.
The first problem was just getting Dependency Injection to work. Once I was able to get that figured out from the sources above I was able to start injecting my services into ViewModels and setting them to the DataContext in the code behind.
Then I ran into an injection issue problem with injecting my IXYZ services into the ViewModels of UserControls.
Pages and their ViewModels worked great but I had issues with the DataContext of the UserControl not being injected with UserControl's ViewModel. They were instead getting injected by the Page's ViewModel that held it.
The final solution turned out to be making sure that the UserControl had the DataContext being set in XAML not the code behind, as we did with the Pages, and then creating a DependencyProperty in the code behind.
To show the basic solution read below.
To make it work I started with:
APP.XAML.CS
public override async Task OnStartAsync(StartKind startKind, IActivatedEventArgs args)
{
// long-running startup tasks go here
RegisterServices();
await Task.CompletedTask;
}
private static void RegisterServices()
{
var services = new ServiceCollection();
services.AddSingleton<IRepository, Repository>();
services.AddSingleton<IBinderService, BinderServices>();
**//ViewModels**
**////User Controls**
services.AddSingleton<AddressesControlViewModel, AddressesControlViewModel>();
services.AddSingleton<CompanyControlViewModel, CompanyControlViewModel>();
**//ViewModels**
**////Pages**
services.AddSingleton<CallListPageViewModel, CallListPageViewModel>();
services.AddSingleton<CallListResultPageViewModel, CallListResultPageViewModel>();
etc....
Container = services.BuildServiceProvider();
}
public override INavigable ResolveForPage(Page page, NavigationService navigationService)
{
**//INJECT THE VIEWMODEL FOR EACH PAGE**
**//ONLY THE PAGE NOT USERCONTROL**
if (page is CallListPage)
{
return Container.GetService<CallListPageViewModel>();
}
if (page is CallListResultPage)
{
return Container.GetService<CallListResultPageViewModel>();
}
etc...
return base.ResolveForPage(page, navigationService);
}
In the code behind for the Page
CALLLISTPAGE.XAML.CS
public CallListPage()
{
InitializeComponent();
}
CallListPageViewModel _viewModel;
public CallListPageViewModel ViewModel
{
get { return _viewModel ?? (_viewModel = (CallListPageViewModel)DataContext); }
}
In your XAML add your UserControl
CALLLISTPAGE.XAML
<binder:CompanyControl Company="{x:Bind ViewModel.SelectedCompany, Mode=TwoWay}"/>
In your UserControl make sure to add the DataContext to the XAML NOT the code behind like we did with the pages.
COMPANYCONTROL.XAML
<UserControl.DataContext>
<viewModels:CompanyControlViewModel x:Name="ViewModel" />
</UserControl.DataContext>
In the UserControl Code Behind add a Dependency Property
COMPANYCONTROL.XAML.CS
public static readonly DependencyProperty CompanyProperty = DependencyProperty.Register(
"Company", typeof(Company), typeof(CompanyControl), new PropertyMetadata(default(Company), SetCompany));
public CompanyControl()
{
InitializeComponent();
}
public Company Company
{
get => (Company) GetValue(CompanyProperty);
set => SetValue(CompanyProperty, value);
}
private static void SetCompany(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
var control = d as CompanyControl;
var viewModel = control?.ViewModel;
if (viewModel != null)
viewModel.Company = (Company) e.NewValue;
}
In the end I am not sure if this is an elegant solution but it works.
Becuase monotouch compile to native code, so it has some limitation such as dynamic invoke is not allowed.
But I have a lot class in .net, that I use the ChannelFactory dynamic to invoke the wcf service: new ChannelFactory(myBinding, myEndpoint); Now in monotouch I should use the slsvcutil to generate the wcf proxy class, but the slsvcutil generate a lot of Unnecessary extra code (huge), and Makes consumers difficult to unit test, due to high coupling with the WCF infrastructure through the ClientBase class.
Is there a better solution except the ChannelFactory? I would rather write the code manually, have more control over how services are invoked such as the ChannelFactory.
==========
ChannelFactory<IMyContract> factory = new ChannelFactory<IMyContract>(binding, endpointAddress);
return factory.CreateChannel();
//==> It throw exception: MonoTouch does not support dynamic proxy code generation. Override this method or its caller to return specific client proxy instance
ChannelFactory<T> has a virtual method CreateChannel(). If this is not overridden, it uses dynamic code generation, which fails on MonoTouch.
The solution is to override it and provide your own compile-time implementation.
Below is an old service implementation of mine that at least used to work on MonoTouch. I split it up into 2 partial classes - the first one being linked in all builds, the 2nd only in the iOS builds (allowing the dynamic generation mechanism to still work on windows).
I've stripped it down to only contain 1 service call.
TransactionService.cs:
public partial class TransactionService : ClientBase<IConsumerService>, IConsumerService
{
public TransactionService()
{
}
public TransactionService(string endpointConfigurationName) :
base(endpointConfigurationName)
{
}
public TransactionService(string endpointConfigurationName, string remoteAddress) :
base(endpointConfigurationName, remoteAddress)
{
}
public TransactionService(string endpointConfigurationName, EndpointAddress remoteAddress) :
base(endpointConfigurationName, remoteAddress)
{
}
public TransactionService(Binding binding, EndpointAddress remoteAddress) :
base(binding, remoteAddress)
{
}
public AccountBalanceResponse GetAccountBalance( AccountBalanceQuery query )
{
return Channel.GetAccountBalance( query );
}
}
TransactionService.iOS.cs:
ConsumerServiceClientChannel which executes the calls via reflection)
public partial class TransactionService
{
protected override IConsumerService CreateChannel()
{
return new ConsumerServiceClientChannel(this);
}
private class ConsumerServiceClientChannel : ChannelBase<IConsumerService>, IConsumerService
{
public ConsumerServiceClientChannel(System.ServiceModel.ClientBase<IConsumerService> client) :
base(client)
{
}
// Sync version
public AccountBalanceResponse GetAccountBalance(AccountBalanceQuery query)
{
object[] _args = new object[1];
_args[0] = query;
return (AccountBalanceResponse)base.Invoke("GetAccountBalance", _args);
}
// Async version
public IAsyncResult BeginGetAccountBalance(AccountBalanceQuery query, AsyncCallback callback, object asyncState )
{
object[] _args = new object[1];
_args[0] = query;
return (IAsyncResult)base.BeginInvoke("GetAccountBalance", _args, callback, asyncState );
}
public AccountBalanceResponse EndGetAccountBalance(IAsyncResult asyncResult)
{
object[] _args = new object[0];
return (AccountBalanceResponse)base.EndInvoke("GetAccountBalance", _args, asyncResult);
}
}
}
EDIT: I just tested this with the latest MT (5.2) - it no longer needs all that extra boiler plate I had in there before, just the CreateChannel() override. I've cleaned up the sample code to match.
EDIT2: I added an async method implementation.
I think you might be confusing terms here - ChannelFactory is a generic type, not a dynamic.
According to MonoTouch documentation, although there's limitations to the Generics support in MonoTouch, ChannelFactory should be okay here.
Have you tried using ChannelFactory?
I have a Data Access Layer, a Service Layer, and a Presentation Layer. The Presentation Layer is ASP.NET MVC2 RTM (web), and the Service Layer is WCF (services). It's all .NET 3.5 SP1.
The problem is that in the services, the objects being returned are marked with the [DataContract] attribute. The web is using the AppFabric Cache (a.k.a Velocity) SessionStateProvider to store session state. Due to this, anything I store in the session must be serializable.
Here comes the problem: the DataContracts aren't marked with [Serializable] and as far as I can remember, by introducing it onto a class already marked with [DataContract] some issues arise, and so I don't believe this is a solution.
I was initially planning on using the DataContracts right in the web layer, using them as models to views related to rendering the DataContracts (probably nested inside a higher level ViewModel class). But due to the session state provider requiring all objects stored inside it to be serializable, I'm starting to rethink this strategy. It would be nice to have though, since they contain validation logic using the IDataErrorInfo interface, and the same validation logic could be re-used in MVC as part of model binding.
What do you believe is the best way to allow me to reduce the work needed?
I've currently thought of the following different ways:
A. Create a 'ServiceIntegration' part in the web project.
This would be a middle man between my controllers and my WCF service layer. The ServiceIntegration part would speak to the service layer using DataContracts, and to the Web layer using ViewModels, but would have to transform between the DataContracts and ViewModels using a two-way Transformer.
Also, since the IDataErrorInfo Validation wouldn't be re-usable, it would be necessary to create a Validator per DataContract too, that uses the Transformer to convert from ViewModel to DataContract, perform validation using IDataErrorInfo and return its results. This would then be used inside action methods of Controllers (e.g. if (!MyValidator.IsValid(viewModel)) return View();)
Different classes required: xDataContract, xViewModel, xTransformer, xValidator
B. Create a 'SessionIntegration' part in the web project
This would be a middle-man between the controllers (or anything accessing the session) and the session itself. Anything requiring access to the session would go through this class. DataContracts would be used in the entire application, unless they are being stored into the session. The SessionIntegration part would take the responsibility of transforming the DataContract to some ISerializable form, and back. No additional Validator is needed because of the use of of IDataErrorInfo interface on the DataContract.
Different classes required: xDataContract, xTransformer, xSerializableForm
Note: there would still be ViewModels around in both scenarios, however with (B) I'd be able to compose ViewModels from DataContracts.
(B) has the benefit of not needing an extra validator.
Before I go off and implement (A)/(B) fully, I'd like some feedback. At the moment, I'm starting to lean towards (B), however, (A) might be more flexible. Either way, it seems like way too much work for what it's worth. Has anyone else come across this problem, do you agree/disagree with me, and/or do you have any other way of solving the problem?
Thanks,
James
Without going the full blown route of A or B, could you just make a generic ISerializable wrapper object and put those in your SessionState?
[Serializable]
public class Wrapper : ISerializable
{
public object Value { get; set; }
void ISerializable.GetObjectData(SerializationInfo info, StreamingContext context)
{
if (Value != null)
{
info.AddValue("IsNull", false);
if (Value.GetType().GetCustomAttributes(typeof(DataContractAttribute), false).Length == 1)
{
using (var ms = new MemoryStream())
{
var serializer = new DataContractSerializer(Value.GetType());
serializer.WriteObject(ms, Value);
info.AddValue("Bytes", ms.ToArray());
info.AddValue("IsDataContract", true);
}
}
else if (Value.GetType().IsSerializable)
{
info.AddValue("Value", Value);
info.AddValue("IsDataContract", false);
}
info.AddValue("Type", Value.GetType());
}
else
{
info.AddValue("IsNull", true);
}
}
public Wrapper(SerializationInfo info, StreamingContext context)
{
if (!info.GetBoolean("IsNull"))
{
var type = info.GetValue("Type", typeof(Type)) as Type;
if (info.GetBoolean("IsDataContract"))
{
using (var ms = new MemoryStream(info.GetValue("Bytes", typeof(byte[])) as byte[]))
{
var serializer = new DataContractSerializer(type);
Value = serializer.ReadObject(ms);
}
}
else
{
Value = info.GetValue("Value", type);
}
}
}
}
As an extension to the provided answer, I added these two methods to ease storing/retrieving the data.
public static void Set<T>(HttpSessionStateBase session, string key, T value)
{
session[key] = new Wrapper(value);
}
public static T Get<T>(HttpSessionStateBase session, string key)
{
object value = session[key];
if (value != null && typeof(T) == value.GetType())
{
return (T) value;
}
Wrapper wrapper = value as Wrapper;
return (T) ((wrapper == null) ? null : wrapper.Value);
}
This makes it a little easier to set/get values from the session:
MyDataContract c = ...;
Wrapper.Set(Session, "mykey", c);
c = Wrapper.Get<MyDataContract>(Session, "mykey");
To make it even easier, add extension methods:
public static class SessionWrapperEx
{
public static void SetWrapped<T>(this HttpSessionStateBase session, string key, T value)
{
Wrapper.Set<T>(session, key, value);
}
public static T GetWrapped<T>(this HttpSessionStateBase session, string key)
{
return Wrapper.Get<T>(session, key);
}
}
And use as below:
MyDataContract c = ...;
Session.SetWrapped("mykey", c);
c = Session.GetWrapped<MyDataContract>("mykey");
I am using Entity Frameowrk 4.0 and I am calling a stored procedure which returns an ObjectResult and I tried to use MOQ and have not been able to mock ObjectResult. Has anybody been able to mock ObjectResult using moq?
TIA
Yaz
I have this problem too; I'm using database-first design, and the EF 4.x DbContext Generator template to generate my DbContext.
I'm modifying the context generator in the following ways:
Instead of DbSet<T> for entity sets, I am returning IDbSet<T>; this allows me to use InMemoryDbSet<T> for unit testing (Google for implementations);
Instead of ObjectResult<T> for stored procedures, I am returning IEnumerable<T>. Inside the virtual method created for the stored procedure, I load the ObjectResult<T> into a List<T> and return that;
Finally, I extract an interface exposing the entity sets and function imports. This means I can then mock the entire DbContext for super-speedy unit tests. You should still write integration tests that test the database functionality for real, of course.
ObjectResult (according to the MSDN docs) is a sealed class as such you cannot mock it. The way Mocking libraries like Moq work is that when you do something like
Mock<Foo> fooMock = new Mock<Foo>();
It generates (using Reflection.Emit and various other magic tricks) a class that looks a little like this
public class FooMockingProxy : Foo {
public override void This() {
// Mocking interceptors to support Verify and Setup
}
public override string That() {
// Mocking interceptors to support Verify and Setup
}
}
i.e. It takes the class (interface) you want to Mock and subclasses it (or implements it in the case of an interface). This allows it to put in instrumentation that allows it to check if a method has been called, or returns a certain value (this supports the various Setup and Verify methods). The restrictions to this method of mocking are:-
Sealed classes (can't be subclassed)
Private members (can't be accessed from a subclass)
Methods or properties classes that are not virtual (and therefore cannot be overriden).
One technique you can take when approaching sealed classes is to wrap them in some kind of interface that is Mockable. Alternatively you can try and Mock an interface that the sealed class implements that only your code consumes.
ObjectResult is typically used with Linq therefore it is mainly used as IEnumerable. Even though object is sealed, you can mock it and setup IEnumerable behavior.
Here is some sample code where TResult is the stored procedure result type and TDbContext is the DbContext and it will return 1 item.
var valueEnumerator = new TResult[] { new TResult() }.GetEnumerator();
var mockStoredProcedure = new Mock<ObjectResult<TResult>();
mockStoredProcedure.Setup(x => x.GetEnumerator()).Returns(valueEnumerator);
var mockEntities = new Mock<TDbContext>();
mockEntities.Setup(x => x.[stored procedure method]()).Returns(mockStoredProcedure.Object);
You can add any values to array in example above or use any other collection (you only need the enumerator).
Give this code a try. It works for me with EF 6.1.2 and Moq 4.2
I could not find a way to mock a sealed class, and wanted to test that the parameters of a stored procedure matched the entity model. Here is my solution:
namespace CardiacMonitoringTest
{
[TestClass]
public class CardiacMonitoringDataTest
{
[TestMethod]
public void TestEntityStoredProcedure()
{
List<string> SPExceptions = new List<string>();
SPExceptions.Add("AfibBurdenByDay");
SPExceptions.Add("GetEventTotalsByCategory");
EntitiesCon db = new EntitiesCon();
foreach (MethodInfo mi in typeof(EntitiesCon).GetMethods())
{
string ptype = mi.ReturnType.Name;
if (ptype.IndexOf("ObjectResult") > -1)
{
List<SqlParameter> ExtractedParameters = SPListParm(ConfigurationManager.ConnectionStrings["CardiacMonitoring"].ConnectionString, mi.Name);
ExtractedParameters = ExtractedParameters.Where(a => a.ParameterName != "#RETURN_VALUE" && a.ParameterName != "#TABLE_RETURN_VALUE").ToList();
ParameterInfo[] EntityParameters = mi.GetParameters();
if ((from b in SPExceptions where b.ToLower() == mi.Name.ToLower() select b).Count() > 0)
{
continue;
}
foreach (ParameterInfo pi in EntityParameters)
{
try
{
Assert.IsTrue(
(from a in ExtractedParameters where pi.Name.ToLower() == a.ParameterName.Replace("#", "").ToLower() select a).Count() == 1);
}
catch (Exception ex)
{
Trace.WriteLine("Failed SP:" + mi.Name + " at parameter:" + pi.Name);
throw (ex);
}
try
{
Assert.IsTrue(EntityParameters.Count() == ExtractedParameters.Count());
}
catch (Exception ex)
{
Trace.WriteLine("Failed SP:" + mi.Name + " on parameter count:" + EntityParameters.Count() + " with detected count as:" + ExtractedParameters.Count());
throw (ex);
}
}
}
}
}
private List<SqlParameter> SPListParm(string ConnectionString, string SPName)
{
try
{
SqlConnection conn = new SqlConnection(ConnectionString);
SqlCommand cmd = new SqlCommand(SPName, conn);
cmd.CommandType = CommandType.StoredProcedure;
conn.Open();
SqlCommandBuilder.DeriveParameters(cmd);
SqlParameter[] prmDetectParameters = new SqlParameter[cmd.Parameters.Count];
cmd.Parameters.CopyTo(prmDetectParameters, 0);
List<SqlParameter> toReturn = new List<SqlParameter>();
toReturn.AddRange(prmDetectParameters);
return (toReturn);
}
catch (Exception ex)
{
Trace.WriteLine("Failed detecting parameters for SP:" + SPName);
throw (ex);
}
}
}
}