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StructureMap HowTo:深对象的条件构造

object-graph structuremap dependency-injection configuration

3

Brett Veenstra · 技术社区 · 16 年前

以下是我在注册表中所做的:

//snip

public SomeRegistry()
{
    this.InstanceOf<IFoo>().Is.Conditional(
        c =>
            {
                c.TheDefault.Is.ConstructedBy(() => new FooZ());

                c.If(
                    p => p.ParentType.IsAssignableFrom(typeof(IBar)) &&
                            p.BuildStack.Current.RequestedType.IsAssignableFrom(typeof(IDoStuffWithFooA)))
                            .ThenIt.Is.ConstructedBy(() => new FooA());
                c.If(
                    p => p.ParentType.IsAssignableFrom(typeof(IBar)) &&
                            p.BuildStack.Current.RequestedType.IsAssignableFrom(typeof(IDoStuffWithFooB)))
                            .ThenIt.Is.ConstructedBy(() => new FooB());
            });

    this.Scan(
        s =>
            {
                s.TheCallingAssembly();
                s.WithDefaultConventions();
            });
}

//snip

下面的单元测试显示了我的期望

//snip

[TestFixture]
public class ConditionalCreationTest
{
    [Test]
    public void GiveUsFooAWhenDoingStuffWithA()
    {
        var dependA = ObjectFactory.GetInstance<IDoStuffWithFooA>();

        Assert.IsInstanceOfType<FooA>(dependA.Foo);
    }

    [Test]
    public void GiveUsFooBWhenDoingStuffWithB()
    {
        var dependB = ObjectFactory.GetInstance<IDoStuffWithFooB>();

        Assert.IsInstanceOfType<FooB>(dependB.Foo);
    }

    [Test]
    public void GiveUsFooZByDefault()
    {
        var foo = ObjectFactory.GetInstance<IFoo>();

        Assert.IsInstanceOfType<FooZ>(foo);
    }

    [Test]
    public void GiveUsProperFoosWhenWeDontAskDirectly()
    {
        var bar = ObjectFactory.GetInstance<IBar>();

        Assert.IsInstanceOfType<FooA>(bar.DoStuffA.Foo);
        Assert.IsInstanceOfType<FooB>(bar.DoStuffB.Foo);
    }

    [SetUp]
    public void SetUp()
    {
        ObjectFactory.Initialize(a => a.AddRegistry<SomeRegistry>());
    }
}
//snip

这就是我希望StructureMap与IFoo的正确依赖关系自动关联的内容:

//snip
    public class Bar : IBar
    {
        private IDoStuffWithFooA doStuffA;
        private IDoStuffWithFooB doStuffB;

        public Bar(IDoStuffWithFooA doStuffA, IDoStuffWithFooB doStuffB)
        {
            this.doStuffA = doStuffA;
            this.doStuffB = doStuffB;
        }

        public IDoStuffWithFooA DoStuffA
        {
            get
            {
                return this.doStuffA;
            }
        }

        public IDoStuffWithFooB DoStuffB
        {
            get
            {
                return this.doStuffB;
            }
        }
    }
//snip

我想不出怎么走 GiveUsProperFoosWhenWeDontAskDirectly

我想得到 FooA 在我需要的时候初始化 IDoStuffWithFooA , FooB IDoStuffWithFooB

1 回复 | 直到 16 年前

1

PHeiberg 15 年前

通常最好避免使用这种语法进行条件构造,因为它比“可供使用”语法更难解释。您的方案可以通过以下方式解决:

        For<IDoStuffWithFooA>().Use<DoStuffWithFooA>().Ctor<IFoo>().Is<FooA>();
        For<IDoStuffWithFooB>().Use<DoStuffWithFooB>().Ctor<IFoo>().Is<FooB>();

        For<IFoo>().Use<FooZ>();

        Scan(
            s =>
            {
                s.TheCallingAssembly();
                s.WithDefaultConventions();
            });