constructor-injection

问题 Having trouble getting the value of a ConstructorArgument parameter passed to kernel.Get(). I want to use the parameter's value to determine which of two string values will be passed into the constructor. The parameter is in fact there when expected, I just can't get at its value. I end up with a null ref exception after calling the parameter's GetValue method: namespace MyNS.DBProviders { public abstract class DBProviderBase { private ObjectContext _db; public DBProviderBase(ObjectContext db

问题 There seems to be an issue with passing generic arguments when attempting to create a parametrized instance with Castle Windsor Demo of Failure to Pass Generic Arguments private static void Main(string[] args) { PassGenericParamAtResolutionTime(); Console.ReadLine(); } private static void PassGenericParamAtResolutionTime() { Console.WriteLine("Passing generic argument fails"); var container = new WindsorContainer(); container.Register(Component.For<ISandCoordinator<Simpleton>>()

问题 Calculators: public interface ICalculator { int Calculate(int a, int b); } public class Calculator : ICalculator { private readonly ICalculatorStrategy _calculatorStrategy; public Calculator(ICalculatorStrategy calculatorStrategy) { _calculatorStrategy = calculatorStrategy; } public int Calculate(int a, int b) { return _calculatorStrategy.Calculate(a, b); } } Calculator stragies: public interface ICalculatorStrategy { int Calculate(int a, int b); } public class AdditionCalculator :

问题 I am new to ASP.Net MVC and multi-tenancy web application. I have done lots of reading, but being a beginner I just follow what I understand. So I managed to built a sample scenario web application and need to solve the ending part of it. Hope this scenario will be useful for some other beginners as well, but would welcome any other approach. Thanks in advance 1) Database in SQLServer 2008. 2) Data layer: C# class library project called MyApplication.Data public class AppUser { [Key] public

问题 When a view model is created you can populate the options (e.g. used in a dropdown list) into a setter property of the view model. The problem is that when that view model is later passed as a parameter (by the framework!) into an action method, those property values has not become automagically repopulated, so if you need to redisplay the form because of validation errors, you need to repopulate those options again. One potential solution, which I am asking for specifically in this question,

问题 I am using Microsoft's Unity for dependency injection and I want to do something like this: IDataContext context = _unityContainer.Resolve<IDataContext>(); var repositoryA = _unityContainer.Resolve<IRepositoryA>(context); //Same instance of context var repositoryB = _unityContainer.Resolve<IRepositoryB>(context); //Same instance of context IDataContext context2 = _unityContainer.Resolve<IDataContext>(); //New instance var repositoryA2 = _unityContainer.Resolve<IRepositoryA>(context2);

问题 I have tried almost everything, but I cannot get AutoMapper to map A => B when B doesn't have a parameterless constructor . I'm using Unity and all the dependencies are registered conveniently but, how do I say to AutoMapper "hey, if the target instance needs some dependency in the constructor, ask Unity to build it, and do the mapping later. I've tried with Mapper.Initialize(configuration => { configuration.ConstructServicesUsing(container.Resolve); configuration.CreateMap<Person,

问题 I have a repository abstract class that encapsulates pretty much all of the CRUD functionality: public abstract class DataRepository<T> : IRepository<T> where T : class { public DataContext Context { get; private set; } public TransactionScope Transaction { get; private set; } /// <summary> /// A <see cref="bool"/> function that compares the keys for fetching a single item, for example: /// return item1.Id == item2.Id (as an anonymous delegate). /// </summary> public Func<T, T, bool>

问题 When I try to pass two parameters that are of the same type like so: public IPercentage CreatePercentage(int part, int total) { return _container.Resolve<T>(new Arguments(part, total)); } To a constructor like so: public Percentage(int part, int total) { // ... } Then I get a System.ArgumentException: An item with the same key has already been added. How can I pass arguments of same type? The key thing is I would like to avoid using literal string names of the parameters to identify which

问题 I'm using .NET Core constructor injection. In a code review from a colleague, he raised the question if I should check for null values on injected dependencies in controllers. Since the framework is responsible for creating an instance of the service, it seems to me that it would take care of any errors and never have a null value dependency passed to a constructor. I don't have any factual evidence for this though, so I'd like to know if it's possible that a null check may be necessary. For