I've been studying this accepted answer to a similar question in which what I believe is a concrete factory returns an implementation based on a string argument on the factory method matching a named binding on the concrete implementation.
I'm struggling to get a slightly more complex example to work properly when the factory is an abstract factory, and I wish to use Ninject convention-based binding. Consider the following test:
[Fact]
public void VehicleBuilderFactory_Creates_Correct_Builder_For_Specified_Client()
{
// arrange
StandardKernel kernel = new StandardKernel();
kernel.Bind(typeof (IVehicleBuilderFactory<,>))
.ToFactory(() => new UseFirstArgumentAsNameInstanceProvider())
.InSingletonScope();
kernel.Bind(scanner => scanner
.FromThisAssembly()
.SelectAllClasses()
.WhichAreNotGeneric()
.InheritedFrom(typeof(IVehicleBuilder<>))
.BindAllInterfaces());
var bicycleBuilderFactory =
kernel.Get<IVehicleBuilderFactory<IVehicleBuilder<BlueBicycle>, BlueBicycle>>();
string country = "Germany";
string localizedColor = "blau";
// act
var builder = bicycleBuilderFactory.Create<IVehicleBuilder<BlueBicycle>>(country);
Bicycle Bicycle = builder.Build(localizedColor);
// assert
Assert.IsType<BlueBicycleBuilder_Germany>(builder);
Assert.IsType<BlueBicycle>(Bicycle);
Assert.Equal(localizedColor, Bicycle.Color);
}
Here's where I try juggling with torches & knives 'cause I saw it on the internet once:
public class UseFirstArgumentAsNameInstanceProvider : StandardInstanceProvider
{
protected override string GetName(MethodInfo methodInfo, object[] arguments) {
return methodInfo.GetGenericArguments()[0].Name + "Builder_" + (string)arguments[0];
// ex: Germany -> 'BlueBicycle' + 'Builder_' + 'Germany' = 'BlueBicyleBuilder_Germany'
}
protected override ConstructorArgument[] GetConstructorArguments(MethodInfo methodInfo, object[] arguments) {
return base.GetConstructorArguments(methodInfo, arguments).Skip(1).ToArray();
}
}
I get stabbed and set ablaze when I try to assign bicycleBuilderFactory
with this error:
System.InvalidCastException was unhandled by user code
Message=Unable to cast object of type 'Castle.Proxies.ObjectProxy' to type 'Ninject.Extensions.Conventions.Tests.IVehicleBuilderFactory`2[Ninject.Extensions.Conventions.Tests.IVehicleBuilder`1[Ninject.Extensions.Conventions.Tests.BlueBicycle],Ninject.Extensions.Conventions.Tests.BlueBicycle]'.
Source=System.Core
StackTrace:
at System.Linq.Enumerable.<CastIterator>d__b1`1.MoveNext()
at System.Linq.Enumerable.Single[TSource](IEnumerable`1 source)
at Ninject.ResolutionExtensions.Get[T](IResolutionRoot root, IParameter[] parameters) in c:\Projects\Ninject\ninject\src\Ninject\Syntax\ResolutionExtensions.cs:line 37
at Ninject.Extensions.Conventions.Tests.NinjectFactoryConventionsTests.VehicleBuilderFactory_Creates_Correct_Builder_For_Specified_Client() in C:\Programming\Ninject.Extensions.Conventions.Tests\NinjectFactoryConventionsTests.cs:line 40
InnerException:
Is it possible to bind using the ToFactory()
method and custom provider, using the factory method argument ("Germany"
) along with the generic type argument (IVehicleBiulder<BlueBicycle>, BlueBicycle
) to resolve the type?
Here's the rest of the code for the test, as compact and readable as I could make it.
public interface IVehicleBuilderFactory<T, TVehicle>
where T : IVehicleBuilder<TVehicle> where TVehicle : IVehicle
{
T Create<T>(string country);
}
VehicleBuilder implementations
public interface IVehicleBuilder<T> where T : IVehicle { T Build(string localizedColor); }
abstract class BicycleBuilder<T> : IVehicleBuilder<T> where T : Bicycle
{
public abstract T Build(string localizedColor);
}
public abstract class RedBicycleBuilder : IVehicleBuilder<RedBicycle>
{
private readonly RedBicycle _Bicycle;
public RedBicycleBuilder(RedBicycle Bicycle) { _Bicycle = Bicycle; }
public RedBicycle Build(string localizedColor)
{
_Bicycle.Color = localizedColor;
return _Bicycle;
}
}
public abstract class GreenBicycleBuilder : IVehicleBuilder<GreenBicycle>
{
private readonly GreenBicycle _Bicycle;
public GreenBicycleBuilder(GreenBicycle Bicycle) { _Bicycle = Bicycle; }
public GreenBicycle Build(string localizedColor)
{
_Bicycle.Color = localizedColor;
return _Bicycle;
}
}
public abstract class BlueBicycleBuilder : IVehicleBuilder<BlueBicycle>
{
private readonly BlueBicycle _Bicycle;
public BlueBicycleBuilder(BlueBicycle Bicycle) { _Bicycle = Bicycle; }
public BlueBicycle Build(string localizedColor)
{
_Bicycle.Color = localizedColor;
return _Bicycle;
}
}
public class RedBicycleBuilder_USA : RedBicycleBuilder {
public RedBicycleBuilder_USA(RedBicycle Bicycle) : base(Bicycle) { }
}
public class RedBicycleBuilder_Germany : RedBicycleBuilder {
public RedBicycleBuilder_Germany(RedBicycle Bicycle) : base(Bicycle) { }
}
public class RedBicycleBuilder_France : RedBicycleBuilder {
public RedBicycleBuilder_France(RedBicycle Bicycle) : base(Bicycle) { }
}
public class RedBicycleBuilder_Default : RedBicycleBuilder {
public RedBicycleBuilder_Default(RedBicycle Bicycle) : base(Bicycle) { }
}
public class GreenBicycleBuilder_USA : GreenBicycleBuilder {
public GreenBicycleBuilder_USA(GreenBicycle Bicycle) : base(Bicycle) { }
}
public class GreenBicycleBuilder_Germany : GreenBicycleBuilder {
public GreenBicycleBuilder_Germany(GreenBicycle Bicycle) : base(Bicycle) { }
}
public class GreenBicycleBuilder_France : GreenBicycleBuilder {
public GreenBicycleBuilder_France(GreenBicycle Bicycle) : base(Bicycle) { }
}
public class GreenBicycleBuilder_Default : GreenBicycleBuilder {
public GreenBicycleBuilder_Default(GreenBicycle Bicycle) : base(Bicycle) { }
}
public class BlueBicycleBuilder_USA : BlueBicycleBuilder
{
public BlueBicycleBuilder_USA(BlueBicycle Bicycle) : base(Bicycle) { }
}
public class BlueBicycleBuilder_Germany : BlueBicycleBuilder {
public BlueBicycleBuilder_Germany(BlueBicycle Bicycle) : base(Bicycle) { }
}
public class BlueBicycleBuilder_France : BlueBicycleBuilder
{
public BlueBicycleBuilder_France(BlueBicycle Bicycle) : base(Bicycle) { }
}
public class BlueBicycleBuilder_Default : BlueBicycleBuilder
{
public BlueBicycleBuilder_Default(BlueBicycle Bicycle) : base(Bicycle) { }
}
Vehicle implementations:
public interface IVehicle { string Color { get; set; } }
public abstract class Vehicle : IVehicle { public string Color { get; set; } }
public abstract class Bicycle : Vehicle { }
public class RedBicycle : Bicycle { }
public class GreenBicycle : Bicycle { }
public class BlueBicycle : Bicycle { }