public partial class CTMSEntitiesModel : OpenAccessContext, ICTMSEntitiesModelUnitOfWork
{
public CTMSEntitiesModel(string connection)
:base(connection, backend, metadataSource)
{ }
// there are more IQueryable requests here
}
public interface ICTMSEntitiesContext : ICTMSEntitiesModelUnitOfWork
{
FetchStrategy FetchStrategy { get; set; }
}
public interface ICTMSEntitiesModelUnitOfWork : IUnitOfWork
{
//all the IQueryable requests are here
}
I need to bind the ICTMSEntitiesContext to CTMSEntitiesModel. How would I go about doing that? What am I doing wrong when I do this? It is throwing an InvalidCastException.
kernel.Bind(typeof(CTMSDAL.ICTMSEntitiesContext)).To(typeof(CTMSDAL.CTMSEntitiesModel)).InRequestScope()
.WithConstructorArgument("connection", System.Configuration.ConfigurationManager.ConnectionStrings["CTMS_MVCConnection"].ConnectionString);
I would appreciate all the help you can provide!
Thanks,
Safris
You have to implement the ICTMSEntitiesContext in the CTMSEntitiesModel class. Otherwise there is no way to cast an instance of the class to the target interface.
Given that you are using OpenAccess and the fact that the context class may be automatically generated I would suggest to you add the interface implementation into a new partial class in different project file to avoid losing the custom code after the original file is regenerated:
public partial class CTMSEntitiesModel : ICTMSEntitiesContext
{
// FetchStrategy property is already defined
}
Related
How do you perform property injection with Simple Injector.
The with Ninject you do is as per bellow:
[Inject]
public IUnitOfWork UnitOfWork { get; set; }
How can I do the equivalent to this with Simple Injector. I tried finding a solution online but had no luck.
Why do I want to use Property Injection?
I want to use property injection to set up unit of work in my base controller so that it will create a new unit of work OnActionExecuting and commit the changes OnResultExecuted. It also means I don't have to pass in the UoW with each new controller I create through the constructor.
Another option is to use the RegisterInitializer method:
container.RegisterInitializer<BaseControllerType>(controller =>
{
controller.UnitOfWork = container.GetInstance<IUnitOfWork>();
}
It keeps all configuration in your composition root and does not pollute your code base with all kinds of attributes.
Update: (as promised)
While this is a direct answer to your question I have to provide you with a better option, because the usage of a base class for this is a IMO not the correct design, for multiple reasons.
Abstract classes can become real PITA classes as they tend to grow towards a god class which has all kinds of cross cutting concerns
An abstract class, especially when used with property injection, hides the needed dependencies.
With focus on point 2. When you want to unit test a controller which inherits from the base controller, you have no way of knowing that this controller is dependent on IUnitOfWork. This you could solve by using constructor injection instead of property injection:
protected abstract class BaseController : Controller
{
protected readonly IUnitOfWork uoW;
protected BaseController (IUnitOfWork uoW)
{
this.uoW = uoW;
}
}
public class SomeController : BaseController
{
public SomeController(IUnitOfWork uoW) : base(uoW) { }
}
While this solves point 2, point 1 is still lurking. The main reason you're wanting this, as you say, is because you do not want to commit your changes in every Action method. Changes must just be saved by the context when the request is done. And thinking about design in this way is a good thing, because Saving changes is, or can be seen as a cross cutting concern and the way you're implementing this is more or less known as AOP.
If it's comes to AOP, especially if you're working with atomic actions in the action methods of your controllers, there is a far better, more SOLID and more flexible design possible which deals with this very nicely.
I'm referring to the Command/Handler pattern which is described in great detail here (also read this for the query part of your application).
With this patterns you don't inject a generic IUnitOfWork abstraction, but inject the specific needed ICommandHandler<TCommand> abstractions.
The action methods would fire the responsible commandhandler for this specific action. All commandhandlers can simple be decorated by a single open-generic SaveChangesCommandHandlerDecorator, 'ValidationDecorator', 'CheckPermissionsDecorator', etc...
A quick example:
public class MoveCustomerCommand
{
public int CustomerId;
public Address NewAddress;
}
public class MoveCustomerCommandHandler : ICommandHandler<MoveCustomerCommand>
{
public void Handle(MoveCustomerCommand command)
{
// retrieve customer from database
// change address
}
}
public class SaveChangesCommandHandlerDecorator<TCommand> : ICommandHandler<TCommand>
{
private readonly ICommandHandler<TCommand> decoratee;
private readonly DbContext db;
public SaveChangesCommandHandlerDecorator(
ICommandHandler<TCommand> decoratee, DbContext db)
{
this.decoratee = decoratee;
this.db = db;
}
public void Handle(TCommand command)
{
this.decoratee.Handle(command);
this.db.SaveChanges();
}
}
// Register as
container.Register(typeof(ICommandHandler<>), new []{Assembly.GetExecutingAssembly() });
container.RegisterDecorator(typeof(ICommandHandler<>),
typeof(SaveChangesCommandHandlerDecorator<>));
// And use in controller as
public ActionResult MoveCustomer(int customerId, Address address)
{
var command = new MoveCustomerCommand
{ CustomerId = customerId, Address = address };
this.commandHandler.Handle(command);
return View(new ResultModel());
}
This keeps your controllers clean and let it do what it must do, namely be the layer between the business logic (the commandhandler implementation in this case) and the view.
Need to create the following:
First create the attribute class
[System.AttributeUsage(System.AttributeTargets.Property]
public class Inject : Attribute
{
}
Then create a custom property behavior
class PropertySelectionBehavior<TAttribute> : IPropertySelectionBehavior
where TAttribute : Attribute
{
public bool SelectProperty(Type type, PropertyInfo prop)
{
return prop.GetCustomAttributes(typeof(TAttribute)).Any();
}
}
Finally tell the container to use custom behavior
container.Options.PropertySelectionBehavior = new PropertySelectionBehavior<Inject>();
All that is left to do is decorate the property with the attribute
[Inject]
public IUnitOfWork UnitOfWork { get; set; }
I've created this code:
public class AddonsModule : Ninject.Modules.NinjectModule
{
public override void Load()
{
this.Bind(b => b.FromAssembliesMatching("*")
.SelectAllClasses()
.InheritedFrom(typeof(UIExtensibility.AbstractAddon))
.BindWith(new AddonBindingGenerator())
);
}
private class AddonBindingGenerator : IBindingGenerator
{
public System.Collections.Generic.IEnumerable<Ninject.Syntax.IBindingWhenInNamedWithOrOnSyntax<object>> CreateBindings(System.Type type, Ninject.Syntax.IBindingRoot bindingRoot)
{
if (type.IsInterface || type.IsAbstract)
yield break;
yield return bindingRoot.Bind(type).ToProvider(typeof(UIExtensibility.AbstractAddon));
}
}
private class AddonProvider : IProvider<UIExtensibility.AbstractAddon>
{
public object Create(IContext context)
{
return null;
}
public Type Type
{
get { throw new NotImplementedException(); }
}
}
}
AddonProvider seems be avoided. This is never performed.
When I perform:
kernel.GetAll<UIExtensibility.AbstractAddon>(), AddonProvider.Create method is never performed.
Could you tell me what's wrong?
I'll appreciate a lot your help.
Thanks for all.
AddOnProvider is inheriting from IProvider<T> instead of UIExtensibility.AbstractAddon.
also, you may have issues binding to private inner classes. make AddOnProvider a public top level class.
You're binding a specific type which inherits from typeof(UIExtensibility.AbstractAddon) to a provider. For example, there could be a class Foo : UIExtensibility.AbstractAddon.
Now your convention binding translates to this:
Bind<Foo>().ToProvider<AddonProvider>();
Now, kernel.GetAll<UIExtensibility.AbstractAddon>() however is looking for bindings made like:
Bind<UIExtensibility.AbstractAddon>().To...
Fix It
So what you need to do is change the line
bindingRoot.Bind(type).ToProvider(new AddonProvider());
to:
bindingRoot.Bind(typeof(UIExtensibility.AbstractAddon)).ToProvider<AddonProvider>();
Furthermore
you're line object f = bindingRoot.Bind(type).ToProvider(new AddonProvider()); is never returning the binding (object f).
does UIExtensibility.AbstractAddon implement IProvider?
Thanks for your answer and comments.
I believe the trouble is on I'm not quite figuring out how this "generic" binding process works.
I'm going to try writing my brain steps process out:
I need to bind every AbstractAddon implementation inside addons assemblies folder. So, I think this code is right, but I'm not sure at all.
this.Bind(b => b.FromAssembliesMatching("*")
.SelectAllClasses()
.InheritedFrom(typeof(UIExtensibility.AbstractAddon))
.BindWith(new AddonBindingGenerator())
);
My AbstractAddon is like:
public abstract class AbstractAddon : IAddon
{
private object configuration;
public AbstractAddon(object configuration)
{
this.configuration = configuration;
}
// IAddon interface
public abstract string PluginId { get; }
public abstract string PluginVersion { get; }
public abstract string getCaption(string key);
public abstract Type getConfigurationPanelType();
public abstract System.Windows.Forms.UserControl createConfigurationPanel();
}
I guess I need to:
foreach implementation of `AbstractAddon` found out,
I need to "inject" a configuration object ->
So, I guess I need to set a provider and provide this configuration object.
This would be my main way of thinking in order to solve this problem.
I've changed a bit my first approach. Instead of using a IBindingGenerator class, I've used the next:
public class AddonsModule : Ninject.Modules.NinjectModule
{
public override void Load()
{
this.Bind(b => b.FromAssembliesMatching("*")
.SelectAllClasses()
.InheritedFrom(typeof(UIExtensibility.AbstractAddon))
.BindAllBaseClasses()
.Configure(c => c.InSingletonScope())
);
this.Bind<object>().ToProvider<ConfigurationProvider>()
.WhenTargetHas<UIExtensibility.ConfigurationAttribute>();
}
So, My ConfigurationProvider is:
private class ConfigurationProvider : IProvider<object>
{
public object Create(IContext context)
{
return "configuration settings";
}
}
And now, my AbstractAddon constructor contains the parameter annotated with ConfigurationAttribute as:
public AbstractAddon([Configuration]object configuration)
{
this.configuration = configuration;
}
The problem now, NInject seems to ignore the configuration object provider. NInject generates a dump object, however, not perform ConfigurationProvider.Create method...
What I'm doing wrong, now?
Is this approach really better than the last one?
Thanks for all.
I am trying to find a way to have a factory class / method that would take in an object or some kind of identifier (string or type) then based off the input parameter determine which implementation of the interface to create and return.
how do I setup my factory method and register the dependency for the interface? following is what I have roughly.
public class ISampleFactory
{
public ISample GetSample(Type type)
{
// do something here to return an implementation of ISample
}
}
public class SampleA : ISample
{
public void DoSomething();
}
public class SampleB : ISample
{
public void DoSomething();
}
public interface ISample
{
void DoSomethin();
}
Have a look at ninject Contextual Bindings Documentation:
You can either use Named Bindings:
this.Bind<ISample>().To<SampleA>().Named("A");
this.Bind<ISample>().To<SampleB>().Named("B");
or a conditional binding with any of the already available extensions or write your own:
this.Bind<ISample>().To<SampleA>().When(...);
this.Bind<ISample>().To<SampleB>().When(...);
see https://github.com/ninject/ninject/wiki/Contextual-Binding
I have installed Ninject (v4.0.30319) package in test project to test. Create test code below, unfortunately ValidateAbuse.Instance.Repository is always Null. Why Ninject do not bind repository to ValidateAbuse.Repository property?
Some of you may suggest to use constructor binding but I can't use it due to code structure. The below code is just example and I need to find a way to bind to property.
Test method which always fail
[TestMethod]
public void PropertyInjection()
{
using (IKernel kernel = new StandardKernel())
{
kernel.Bind<ISettingsRepository>().To<SettingsRepository>();
Assert.IsNotNull(ValidateAbuse.Instance.Repository);
}
}
The repository interface
public interface ISettingsRepository
{
List<string> GetIpAbuseList();
List<string> GetSourceAbuseList();
}
The repository implementation
public class SettingsRepository : ISettingsRepository
{
public List<string> GetIpAbuseList()
{
return DataAccess.Instance.Abuses.Where(p => p.TypeId == 1).Select(p => p.Source).ToList();
}
public List<string> GetSourceAbuseList()
{
return DataAccess.Instance.Abuses.Where(p => p.TypeId == 2).Select(p => p.Source).ToList();
}
}
The class to which I am trying to bind repository
public class ValidateAbuse
{
[Inject]
public ISettingsRepository Repository { get; set; }
public static ValidateAbuse Instance = new ValidateAbuse();
}
Ninject will only bind properties on an object when it creates an instance of that object. Since you are creating the instance of ValidateAbuse rather than Ninject creating it, it won't know anything about it and therefore be unable to set the property values upon creation.
EDIT:
You should remove the static singleton from ValidateAbuse and allow Ninject to manage it as a singleton.
kernel.Bind<ValidateAbuse>().ToSelf().InSingletonScope();
Then when you ask Ninject to create any class that needs an instance of ValidateAbuse, it will always get the same instance.
It seems like you don't fully understand how Ninject works or how to implement it so I would suggest you read the wiki https://github.com/ninject/ninject/wiki/How-Injection-Works and follow some more basic examples before trying to wire it into an existing application.
I created a LoggerDomainService witch look like this :
[EnableClientAccess()]
public class LoggerDomainService : DomainService
{
public void info()
{
// todo
}
}
And after building the server side the LoggerDomainContext did not created.
I've noticed that in order to make it work I need to declare inside the class at least on method with the [Query] attribute.
Is there better way to solver the problem, should I inherit from something else then DomainService ?
You are correct about the [Query] attribute. With your logging service, I recommend using [Invoke]:
[EnableClientAccess()]
public class LoggerDomainService : DomainService
{
[Invoke]
public void info()
{
// todo
}
}
Then you will find the context created.