c# - PRISM + MEF -- 导入 & ImportMany

Question

FooService.cs:

public interface IFooService
{
    int Foo();
}

[Export("Foo1", typeof(IFooService))]
public class Foo1 : IFooService
{
    public int Foo() { return 1; }
}


[Export("Foo2", typeof(IFooService))]
public class Foo2 : IFooService
{
    public int Foo() { return 2; }
}

FooViewModel.cs:

public class FooViewModel : NotificationObject
{
    [ImportMany(typeof(IFooService))]
    public IEnumerable<IFooService> FooServices { get; private set; }

    [Import("Foo1")]
    public IFooService FirstFoo { get; private set; }
}

---

单一导入有效，因为我有一个命名契约(Contract)，但多重导入没有。如果我更改导出属性并删除命名契约(Contract)，则多导入有效，但单导入无效。如何让两者同时工作？

Answer 1

您可以在您的类上放置多个导出属性:

[Export(typeof(IFooService))]
[Export("Foo1", typeof(IFooService))]
public class Foo1 : IFooService
{
    public int Foo() { return 1; }
}

[Export(typeof(IFooService))]
[Export("Foo2", typeof(IFooService))]
public class Foo2 : IFooService
{
    public int Foo() { return 2; }
}