Question

我一直在使用Ninject作为XNA项目的IOC，并希望将其迁移到Ninject 2.0。但是，XNA不是依赖注入友好的，因为某些类必须在游戏类的构造函数中实例化，但必须将游戏类传递给它们的构造函数。例如：

public MyGame ()
{
    this.graphicsDeviceManager = new GraphicsDeviceManager (this);
}

文章here描述了一种解决方法，其中明确告知IOC容器用于解析服务的实例。

/// <summary>Initializes a new Ninject game instance</summary>
/// <param name="kernel">Kernel the game has been created by</param>
public NinjectGame (IKernel kernel)
{
    Type type = this.GetType ();

    if (type != typeof (Game))
    {
        this.bindToThis (kernel, type);
    }
    this.bindToThis (kernel, typeof (Game));
    this.bindToThis (kernel, typeof (NinjectGame));
}

/// <summary>Binds the provided type to this instance</summary>
/// <param name="kernel">Kernel the binding will be registered to</param>
/// <param name="serviceType">Service to which this instance will be bound</param>
private void bindToThis (IKernel kernel, Type serviceType)
{
    StandardBinding binding = new StandardBinding (kernel, serviceType);
    IBindingTargetSyntax binder = new StandardBinder (binding);

    binder.ToConstant (this);
    kernel.AddBinding (binding);
}

但是，我不确定如何在Ninject 2.0中实现这一点，因为我认为是等效的代码

if (type != typeof (Game))
{
    kernel.Bind (type).ToConstant (this).InSingletonScope ();
}
kernel.Bind (typeof (Game)).ToConstant (this).InSingletonScope ();
kernel.Bind (typeof (NinjectGame)).ToConstant (this).InSingletonScope ();

仍会产生StackOverflowException。任何关于至少从哪里开始的想法都将不胜感激。

Answer 1

如果再次调用MyGame，问题似乎来自Ninject不会自动替换之前在NinjectGame，Game和Bind()之间设置的绑定。解决方案是再次调用Unbind()，然后调用Bind()，或者只调用Rebind()，这是我选择做的事情

if (type != typeof (Game))
{
    kernel.Rebind (type).ToConstant (this).InSingletonScope ();
}
kernel.Rebind (typeof (Game)).ToConstant (this).InSingletonScope ();
kernel.Rebind (typeof (NinjectGame)).ToConstant (this).InSingletonScope ();

因为如果在调用之前不存在绑定，它不会抛出异常或引起任何其他问题。

使用Ninject 2.0避免XNA中的循环依赖

1 个答案: