I am new to developing application in Xamarin Android. I integrated AndroidX.lifeCycle using nuggets. I know how to create an object private MutableLiveData currentName = new MutableLiveData();
in java Android. but difficult to create an object in Xamarin Android. Any one has idea how to use LiveData in Xamarin Android
You should install the Xamarin.Android.Arch.Lifecycle.LiveData nuget.Package first, right click your Xamarin.Android project and choose Manage Nuget Packages.., then search the package and install it as showed in below screenshot:
Then in your project, use the namespace and code :
using Android.Arch.Lifecycle;
MutableLiveData currentName = new MutableLiveData();
Update:
public class MainActivity : AppCompatActivity
{
protected override void OnCreate(Bundle savedInstanceState)
{
base.OnCreate(savedInstanceState);
MutableLiveData currentName = new MutableLiveData();
currentName.SetValue("321");
mylifeCycle lifeCycle = new mylifeCycle();
mylObserver obsever = new mylObserver();
currentName.Observe(lifeCycle, obsever);
}
}
public class mylifeCycle : ILifecycleOwner
{
public Lifecycle Lifecycle => throw new NotImplementedException();
public IntPtr Handle => throw new NotImplementedException();
public void Dispose()
{
throw new NotImplementedException();
}
}
public class mylObserver : IObserver
{
public IntPtr Handle => throw new NotImplementedException();
public void Dispose()
{
throw new NotImplementedException();
}
public void OnChanged(Java.Lang.Object p0)
{
throw new NotImplementedException();
}
}
I think the confusion is caused by the fact that the Xamarin API is referencing java objects.
When i created seprated class to implement IObserver then i had to implement alot of method. But noticed in your code you just override two methods. ?
That's because IObserver is a java interface. If you inherit from Java.Lang.Object then you just need to implement the one method:
class MyObserver : Java.Lang.Object, IObserver
{
public void OnChanged (Java.Lang.Object o)
{
}
}
Alternatively you could implement IObserver in an existing class that already inherits from Java.Lang.Object, e.g. your Adapter class.
Did you know how to covert C# object to java.lang.object ?
I think you're refering to the fact that the LiveData object, that is being observed, is a Java.Lang.Object.
In my case I wanted to observe a C# object, specifically a System.Collections.Generic.List. But this is not allowed as there is no way to convert between the System object and a Java object.
My solution was to use an Android.Runtime.JavaList object. This is a Java object and implements System.Collections.Generic.IList so I didn't have to go digging into the Java class hierarchy, I just used the C# IList methods.
IMHO the fact that we need to use java objects at all suggests that this is an area that the Xamarin team haven't prioritised.
Related
I've read and Googled everything on this, but can't seem to get it to work. I created a custom LifetimeManager for Unity in my MVC5 application based on these posts:
MVC3 Unity Framework and Per Session Lifetime Manager
This may be the issue I am experiencing
Here is my SessionLifetimeManager
public class SessionLifetimeManager : LifetimeManager
{
private string key = Guid.NewGuid().ToString();
public override object GetValue()
{
return HttpContext.Current.Session[key];
}
public override void RemoveValue()
{
HttpContext.Current.Session.Remove(key);
}
public override void SetValue(object newValue)
{
HttpContext.Current.Session[key] = newValue;
}
}
I only have a few types I'm playing with, here is the relevant registrations in UnityConfig.cs:
container.RegisterType<IEpiSession, EpiSession>(new SessionLifetimeManager(),
new InjectionConstructor(config.AppServerURI, config.PathToSysConfig));
container.RegisterType<IReportRepository, EpicorReportRepository>(new TransientLifetimeManager());
DependencyResolver.SetResolver(new UnityDependencyResolver(container));
Note that the EpicorReportRepository has a dependency on IEpiSession via constructor injection.
public class EpicorReportRepository : IReportRepository
{
private IEpiSession session;
// DI constructor
public EpicorReportRepository(IEpiSession session) {
this.session = session;
}
// ...
}
My Problem: After the first user / session connects to the application, every new user / session after that seems to still be using the EpiSession object and credentials that the first user had create/injected for him. This seems to be a common pattern used on the interwebs, so I'm wondering what I am missing.
How did you test that IEpiSession is the same in different Sessions?
Try to open you application from different browsers. If you open several tabs in the same browser then the same session is used.
I checked your code and it works for me.
There is the only one difference in SetResolver():
DependencyResolver.SetResolver(
type => container.Resolve(type),
types => container.ResolveAll(types));
The full registration code is the following:
public class MvcApplication : System.Web.HttpApplication
{
protected void Application_Start()
{
...
var container = new UnityContainer();
container.RegisterType<IEpiSession, EpiSession>(
new SessionLifetimeManager(),
new InjectionConstructor("config.AppServerURI", "config.PathToSysConfig"));
container.RegisterType<IReportRepository, EpicorReportRepository>(new TransientLifetimeManager());
DependencyResolver.SetResolver(
type => container.Resolve(type),
types => container.ResolveAll(types));
}
}
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?
Is there any way to gain access to the controller that is currently executing from within Global.asax?
I'd like to design an API with similar syntax to:
MyClass.RegisterComponents().When(IController => /* Some condition */)
Although I could move this code to a place where the controller is in context, I'd like to keep it centralised and portable.
So far, I have been unable to obtain the controller. Any ideas?
I have considered creating a base controller and extending all of my controllers from this base class, however, I'd like to make this library portable with the ability to be installed via NuGet. For this reason I am unable to take this approach.
You can do following in your global.asmx file.
private void Application_BeginRequest(object sender, EventArgs e)
{
string controllerName = Request.RequestContext.RouteData.Values.Where(p => p.Key =="controller").FirstOrDefault(p => p.Key);
}
I found a solution to this. Not a very good one but it solves my problem.
Register a global IActionFilter using an assembly start up method I found on David Ebbo's blog (http://blog.davidebbo.com/2011/02/register-your-http-modules-at-runtime.html).
The global action filter simply stores the action context in the current HttpContext.Items[] collection which is a per request collection.
public class GlobalActionFilter : System.Web.Mvc.IActionFilter {
internal static readonly object ActionExecutedFilterKey =
"__MvcResourceLoaderActionExecutedContext";
internal static readonly object ActionExecutingFilterKey =
"__MvcResourceLoaderActionExecutingContext";
static MvcResourceLoaderGlobalFilter __instance =
new MvcResourceLoaderGlobalFilter();
MvcResourceLoaderGlobalFilter() { }
public void OnActionExecuted(System.Web.Mvc.ActionExecutedContext filterContext) {
System.Web.HttpContext.Current.Items[ActionExecutedFilterKey] =
filterContext;
}
public void OnActionExecuting(System.Web.Mvc.ActionExecutingContext filterContext) {
System.Web.HttpContext.Current.Items[ActionExecutingFilterKey] =
filterContext;
}
public static void RegisterGlobalFilter() {
if (!System.Web.Mvc.GlobalFilters.Filters.Contains(__instance))
System.Web.Mvc.GlobalFilters.Filters.Add(__instance);
}
}
I can then access the context anywhere.
I have an application using ASP.NET MVC, Unity, and Linq to SQL.
The unity container registers the type AcmeDataContext which inherits from System.Data.Linq.DataContext, with a LifetimeManager using HttpContext.
There is a controller factory which gets the controller instances using the unity container. I set-up all my dependencies on the constructors, like this:
// Initialize a new instance of the EmployeeController class
public EmployeeController(IEmployeeService service)
// Initializes a new instance of the EmployeeService class
public EmployeeService(IEmployeeRepository repository) : IEmployeeService
// Initialize a new instance of the EmployeeRepository class
public EmployeeRepository(AcmeDataContext dataContext) : IEmployeeRepository
Whenever a constructor is needed, the unity container resolves a connection, which is used to resolve a data context, then a repository, then a service, and finally the controller.
The issue is that IEmployeeRepository exposes the SubmitChanges method, since the service classes DO NOT have a DataContext reference.
I have been told that the unit of work should be managed from outside the repositories, so it would seem I ought to remove SubmitChanges from my repositories. Why is that?
If this is true, does this mean that I have to declare an IUnitOfWork interface and make every service class dependent upon it? How else can I allow my service classes to manage the unit of work?
You shouldn't try to supply the AcmeDataContext itself to the EmployeeRepository. I would even turn the whole thing around:
Define a factory that allows creating a new unit of work for the Acme domain:
Create an abstract AcmeUnitOfWork that abstracts away LINQ to SQL.
Create a concrete factory that can allows creating new LINQ to SQL unit of works.
Register that concrete factory in your DI configuration.
Implement an InMemoryAcmeUnitOfWork for unit testing.
Optionally implement convenient extension methods for common operations on your IQueryable<T> repositories.
UPDATE: I wrote a blog post on this subject: Faking your LINQ provider.
Below is a step-by-step with examples:
WARNING: This will be a loooong post.
Step 1: Defining the factory:
public interface IAcmeUnitOfWorkFactory
{
AcmeUnitOfWork CreateNew();
}
Creating a factory is important, because the DataContext implement IDisposable so you want to have ownership over the instance. While some frameworks allow you to dispose objects when not needed anymore, factories make this very explicit.
Step 2: Creating an abstract unit of work for the Acme domain:
public abstract class AcmeUnitOfWork : IDisposable
{
public IQueryable<Employee> Employees
{
[DebuggerStepThrough]
get { return this.GetRepository<Employee>(); }
}
public IQueryable<Order> Orders
{
[DebuggerStepThrough]
get { return this.GetRepository<Order>(); }
}
public abstract void Insert(object entity);
public abstract void Delete(object entity);
public abstract void SubmitChanges();
public void Dispose()
{
this.Dispose(true);
GC.SuppressFinalize(this);
}
protected abstract IQueryable<T> GetRepository<T>()
where T : class;
protected virtual void Dispose(bool disposing) { }
}
There are some interesting things to note about this abstract class. The Unit of Work controls and creates the Repositories. A repository is basically something that implements IQueryable<T>. The repository implements properties that return a specific repository. This prevents users from calling uow.GetRepository<Employee>() and this creates a model that is very close to what you are already doing with LINQ to SQL or Entity Framework.
The unit of work implements Insert and Delete operations. In LINQ to SQL these operations are placed on the Table<T> classes, but when you try to implement it this way it will prevent you from abstracting LINQ to SQL away.
Step 3. Create a concrete factory:
public class LinqToSqlAcmeUnitOfWorkFactory : IAcmeUnitOfWorkFactory
{
private static readonly MappingSource Mapping =
new AttributeMappingSource();
public string AcmeConnectionString { get; set; }
public AcmeUnitOfWork CreateNew()
{
var context = new DataContext(this.AcmeConnectionString, Mapping);
return new LinqToSqlAcmeUnitOfWork(context);
}
}
The factory created a LinqToSqlAcmeUnitOfWork based on the AcmeUnitOfWork base class:
internal sealed class LinqToSqlAcmeUnitOfWork : AcmeUnitOfWork
{
private readonly DataContext db;
public LinqToSqlAcmeUnitOfWork(DataContext db) { this.db = db; }
public override void Insert(object entity)
{
if (entity == null) throw new ArgumentNullException("entity");
this.db.GetTable(entity.GetType()).InsertOnSubmit(entity);
}
public override void Delete(object entity)
{
if (entity == null) throw new ArgumentNullException("entity");
this.db.GetTable(entity.GetType()).DeleteOnSubmit(entity);
}
public override void SubmitChanges();
{
this.db.SubmitChanges();
}
protected override IQueryable<TEntity> GetRepository<TEntity>()
where TEntity : class
{
return this.db.GetTable<TEntity>();
}
protected override void Dispose(bool disposing) { this.db.Dispose(); }
}
Step 4: Register that concrete factory in your DI configuration.
You know self best how to register the IAcmeUnitOfWorkFactory interface to return an instance of the LinqToSqlAcmeUnitOfWorkFactory, but it would look something like this:
container.RegisterSingle<IAcmeUnitOfWorkFactory>(
new LinqToSqlAcmeUnitOfWorkFactory()
{
AcmeConnectionString =
AppSettings.ConnectionStrings["ACME"].ConnectionString
});
Now you can change the dependencies on the EmployeeService to use the IAcmeUnitOfWorkFactory:
public class EmployeeService : IEmployeeService
{
public EmployeeService(IAcmeUnitOfWorkFactory contextFactory) { ... }
public Employee[] GetAll()
{
using (var context = this.contextFactory.CreateNew())
{
// This just works like a real L2S DataObject.
return context.Employees.ToArray();
}
}
}
Note that you could even remove the IEmployeeService interface and let the controller use the EmployeeService directly. You don't need this interface for unit testing, because you can replace the unit of work during testing preventing the EmployeeService from accessing the database. This will probably also save you a lot of DI configuration, because most DI frameworks know how to instantiate a concrete class.
Step 5: Implement an InMemoryAcmeUnitOfWork for unit testing.
All these abstractions are there for a reason. Unit testing. Now let's create a AcmeUnitOfWork for unit testing purposes:
public class InMemoryAcmeUnitOfWork: AcmeUnitOfWork, IAcmeUnitOfWorkFactory
{
private readonly List<object> committed = new List<object>();
private readonly List<object> uncommittedInserts = new List<object>();
private readonly List<object> uncommittedDeletes = new List<object>();
// This is a dirty trick. This UoW is also it's own factory.
// This makes writing unit tests easier.
AcmeUnitOfWork IAcmeUnitOfWorkFactory.CreateNew() { return this; }
// Get a list with all committed objects of the requested type.
public IEnumerable<TEntity> Committed<TEntity>() where TEntity : class
{
return this.committed.OfType<TEntity>();
}
protected override IQueryable<TEntity> GetRepository<TEntity>()
{
// Only return committed objects. Same behavior as L2S and EF.
return this.committed.OfType<TEntity>().AsQueryable();
}
// Directly add an object to the 'database'. Useful during test setup.
public void AddCommitted(object entity)
{
this.committed.Add(entity);
}
public override void Insert(object entity)
{
this.uncommittedInserts.Add(entity);
}
public override void Delete(object entity)
{
if (!this.committed.Contains(entity))
Assert.Fail("Entity does not exist.");
this.uncommittedDeletes.Add(entity);
}
public override void SubmitChanges()
{
this.committed.AddRange(this.uncommittedInserts);
this.uncommittedInserts.Clear();
this.committed.RemoveAll(
e => this.uncommittedDeletes.Contains(e));
this.uncommittedDeletes.Clear();
}
protected override void Dispose(bool disposing)
{
}
}
You can use this class in your unit tests. For instance:
[TestMethod]
public void ControllerTest1()
{
// Arrange
var context = new InMemoryAcmeUnitOfWork();
var controller = new CreateValidController(context);
context.AddCommitted(new Employee()
{
Id = 6,
Name = ".NET Junkie"
});
// Act
controller.DoSomething();
// Assert
Assert.IsTrue(ExpectSomething);
}
private static EmployeeController CreateValidController(
IAcmeUnitOfWorkFactory factory)
{
return new EmployeeController(return new EmployeeService(factory));
}
Step 6: Optionally implement convenient extension methods:
Repositories are expected to have convenient methods such as GetById or GetByLastName. Of course IQueryable<T> is a generic interface and does not contains such methods. We could clutter our code with calls like context.Employees.Single(e => e.Id == employeeId), but that's really ugly. The perfect solution to this problem is: extension methods:
// Place this class in the same namespace as your LINQ to SQL entities.
public static class AcmeRepositoryExtensions
{
public static Employee GetById(this IQueryable<Employee> repository,int id)
{
return Single(repository.Where(entity => entity.Id == id), id);
}
public static Order GetById(this IQueryable<Order> repository, int id)
{
return Single(repository.Where(entity => entity.Id == id), id);
}
// This method allows reporting more descriptive error messages.
[DebuggerStepThrough]
private static TEntity Single<TEntity, TKey>(IQueryable<TEntity> query,
TKey key) where TEntity : class
{
try
{
return query.Single();
}
catch (Exception ex)
{
throw new InvalidOperationException("There was an error " +
"getting a single element of type " + typeof(TEntity)
.FullName + " with key '" + key + "'. " + ex.Message, ex);
}
}
}
With these extension methods in place, it allows you to call those GetById and other methods from your code:
var employee = context.Employees.GetById(employeeId);
What the nicest thing is about this code (I use it in production) is that -once in place- it saves you from writing a lot of code for unit testing. You will find yourself adding methods to the AcmeRepositoryExtensions class and properties to the AcmeUnitOfWork class when new entities are added to the system, but you don't need to create new repository classes for production or testing.
This model has of course some shortcomes. The most important perhaps is that LINQ to SQL isn't abstract away completely, because you still use the LINQ to SQL generated entities. Those entity contain EntitySet<T> properties which are specific to LINQ to SQL. I haven't found them to be in the way of proper unit testing, so for me it's not a problem. If you want you can always use POCO objects with LINQ to SQL.
Another shortcome is that complicated LINQ queries can succeed in test but fail in production, because of limitations (or bugs) in the query provider (especially the EF 3.5 query provider sucks). When you do not use this model, you are probably writing custom repository classes that are completely replaced by unit test versions and you will still have the problem of not being able to test queries to your database in unit tests. For this you will need integration tests, wrapped by a transaction.
A last shortcome of this design is the use of Insert and Delete methods on the Unit of Work. While moving them to the repository would force you to have a design with an specific class IRepository<T> : IQueryable<T> interface, it prevents you from other errors. In the solution I use myself I also have InsertAll(IEnumerable) and DeleteAll(IEnumerable) methods. It is however easy to mistype this and write something like context.Delete(context.Messages) (note the use of Delete instead of DeleteAll). This would compile fine, because Delete accepts an object. A design with delete operations on the repository would prevent such statement from compiling, because the repositories are typed.
UPDATE: I wrote a blog post on this subject that describes this solution in even more detail: Faking your LINQ provider.
I hope this helps.
If combining unit of work and repository patterns, some people advocate that UoW should be managed outside of repository so that you could create two repositories (say, CustomerRepository and OrderRepository) and pass them the same UoW instance ensuring that all the changes to the DB will be done atomically when you finally call UoW.Complete().
In a mature DDD solution however, there should not be need for both UoW and a repository. This is because is such a solution aggregate boundaries are defined is such a way, that there is no need of atomic changes involving more than one repository.
Does this answer your question?
I'm building small web shop with asp.net mvc and Structuremap ioc/di. My Basket class uses session object for persistence, and I want use SM to create my basket object through IBasket interface. My basket implementation need HttpSessionStateBase (session state wrapper from mvc) in constructor, which is available inside Controller/Action. How do I register my IBasket implementation for SM?
This is my basket interface:
public interface IBasketService {
BasketContent GetBasket();
void AddItem(Product productItem);
void RemoveItem(Guid guid);
}
And SM registration:
ForRequestedType(typeof (IBasketService)).TheDefaultIsConcreteType(typeof (StoreBasketService));
But my StoreBasketService implementation has constructor:
public StoreBasketService(HttpSessionStateBase sessionState)
How do I provide HttpSessionStateBase object to SM, which is available only in controller?
This is my first use of SM IOC/DI, and cann't find solution/example in official documentation and web site ;)
If you absolutely have to have your StoreBasketService use the session, I'd be tempted to define an interface and wrapper around HttpSessionState instead of using HttpSessionStateBase so that you can register it with StructureMap as well.The wrapper would get the session state from the current context. Register the wrapper with StructureMap and then have your StoreBasketService take the interface as the argument to the constructor. Structure map should then know how to create an instance of the interface wrapper and inject it into your StoreBasketService class.
Using an interface and wrapper will allow you to mock the wrapper in your unit tests, muc in the same way HttpSessionStateBase allows mocking the actual session.
public interface IHttpSessionStateWrapper
{
HttpSessionState GetSessionState();
}
public class HttpSessionStateWrapper : IHttpSessionStateWrapper
{
public virtual HttpSessionState GetSessionState()
{
return HttpContext.Current.Session;
}
}
ForRquestedType(typeof(IHttpSessionStateWrapper))
.TheDefaultIsConcreteType(typeof(IHttpSessionStateWrapper));
public class StoreBasketService
{
HttpSessionState session;
public StoreBasketService( IHttpSessionstateWrapper wrapper )
{
session = wrapper.GetSessionState();
}
// basket implementation ...
}
However, you can have StructureMap actually store your basket in the session using .CacheBy(InstanceScope.HttpContext) when registering it. It may actually be better to have your StoreBasketService implement internal storage instead of storing things in the session -- then you lose the dependency on the session state entirely (from the perspective of your class) and your solution could be simpler. Your internal storage could be a Dictionary<Guid,Product> since this is how you access them via your interface.
See also:
http://www.lostechies.com/blogs/chad_myers/archive/2008/07/15/structuremap-basic-scenario-usage.aspx
http://www.lostechies.com/blogs/chad_myers/archive/2008/07/17/structuremap-medium-level-usage-scenarios.aspx
ForRequestedType<IBasketService>()
.TheDefault.Is.OfConcreteType<StoreBasketService>()
.WithCtorArg("sessionState").EqualTo(HttpContext.Current.Session);
?? does that work?
I just started with StructureMap, and I do not get the results you are describing.
I performed a simple test using a simple class, configuring Structuremap to cacheby HttpContext, and from what I can see, CacheBy.HttpContext means within the same request you will get the same instance... not within the same Session
The constructor of my class, sets the date/time in a private field
I have a button which gets 2 instances of MyClass with one second interval...
It then display the time of both instances in a label.
Pressing the first time this button, object A and B are same instance, as their creation time is exactly the same, as expected.
Clicking the button a second time, you would expect the creation time to not have changed if instances would be cached in session... however, in my test I get a new creation time ...
Structuremap configuration:
ObjectFactory.Initialize(x=>x.ForRequestedType<MyClass>(). CacheBy(InstanceScope.HttpContext));
Button clicked event of test page
protected void btnTest_Click(object sender, EventArgs e)
{
MyClass c = ObjectFactory.GetInstance<MyClass>();
System.Threading.Thread.Sleep(1000);
MyClass b = ObjectFactory.GetInstance<MyClass>();
lblResult.Text = String.Format("cache by httpcontext First:{0} Second:{1} session id {2} ", c.GetTimeCreated(), b.GetTimeCreated(),Session.SessionID);
}
MyClass
public class MyClass
{
private DateTime _timeCreated;
public MyClass()
{
_timeCreated = DateTime.Now;
}
public string GetTimeCreated()
{
return _timeCreated.ToString("dd/MM/yyyy hh:mm:ss");
}
}
You could also use one of the ObjectFactory.Inject methods to inject the HttpSessionStateBase into StructureMap. It would then invoke the constructor with the injected HttpSessionStateBase.
I just made my first attempt at creating an custom scope... build a small web application with it, and as far as I can see, it seems to work. This will cache the object inside the current user session and will return the same object as long as you remain inside the same session:
public class HttpSessionBuilder : CacheInterceptor
{
private readonly string _prefix = Guid.NewGuid().ToString();
protected override CacheInterceptor clone()
{
return this;
}
private string getKey(string instanceKey, Type pluginType)
{
return string.Format("{0}:{1}:{2}", pluginType.AssemblyQualifiedName, instanceKey, this._prefix);
}
public static bool HasContext()
{
return (HttpContext.Current.Session != null);
}
protected override bool isCached(string instanceKey, Type pluginType)
{
return HttpContext.Current.Session[this.getKey(instanceKey, pluginType)] != null;
}
protected override object retrieveFromCache(string instanceKey, Type pluginType)
{
return HttpContext.Current.Session[this.getKey(instanceKey, pluginType)];
}
protected override void storeInCache(string instanceKey, Type pluginType, object instance)
{
HttpContext.Current.Session.Add(this.getKey(instanceKey, pluginType), instance);
}
}
You have to configure the ObjectFactory as follows in the global.asax Application_start
ObjectFactory.Initialize(x=>
x.ForRequestedType<MyClass>().InterceptConstructionWith(new HttpSessionBuilder()));