Ninject 2.0的上下文绑定 [英] Contextual bindings with Ninject 2.0

问题描述

在Ninject 1.0中，我具有以下绑定定义:

In Ninject 1.0 I had following binding definitions:

Bind<ITarget>().To<Target1>().Only(When.Context.Variable("variable").EqualTo(true));
Bind<ITarget>().To<Target2>();

考虑到我曾经打电话给的这种绑定:

Given such bindings I had calls:

ITarget target = kernel.Get<ITarget>(With.Parameters.ContextVariable("variable", true));
ITarget target = kernel.Get<ITarget>(With.Parameters.ContextVariable("variable", false));

第一次调用已解析为Target1的实例，第二次调用已解析为Target2的实例.

First call was resolved to instance of Target1, second call was resolved to instance of Target2.

如何将其转换为Ninject 2.0?

How to translate this into Ninject 2.0?

推荐答案

您可以使用元数据，

[Fact]
public void MetadataBindingExample()
{
    string metaDataKey = "key";
    kernel.Bind<IWeapon>().To<Shuriken>().WithMetadata(metaDataKey, true);
    kernel.Bind<IWeapon>().To<Sword>().WithMetadata(metaDataKey, false);
    kernel.Bind<IWeapon>().To<Knife>();

    var weapon = kernel.Get<IWeapon>(metadata => metadata.Has(metaDataKey) && metadata.Get<bool>(metaDataKey));
    Assert.IsType<Shuriken>( weapon );

    weapon = kernel.Get<IWeapon>(metadata => metadata.Has(metaDataKey) && !metadata.Get<bool>(metaDataKey));
    Assert.IsType<Sword>(weapon);

    weapon = kernel.Get<IWeapon>(metadata => !metadata.Has(metaDataKey));
    Assert.IsType<Knife>(weapon);
}

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