依赖注入 - 当前上下文中不存在名称"Bind" - MethodAccessException未处理

Question

代码示例:

namespace DependencyInjection
{
class Program  
{
    static void Main(string[] args)
    {
        IKernel kernel = new StandardKernel();
        var samurai = kernel.Get<Samurai>();
        Bind<IWeapon>().To<Sword>();
   }       
}



class Samurai
{
    readonly IWeapon _weapon;
    public Samurai(IWeapon weapon)
    {
        _weapon = weapon;
    }
    public void Attack(string target)
    {
        _weapon.Hit(target);
    }
}

interface IWeapon
{
    void Hit(string target);
}

class Sword : IWeapon
{
    public void Hit(string target)
    {
        Console.WriteLine("Sword - ", target);
    }
}

class Arrow : IWeapon
{
    public void Hit(string target)
    {
        Console.WriteLine("Arrow - ", target);
    }
}
}

这是我第一次尝试使用ninject实现DI.

我不知道如何解决错误"当前上下文中不存在名称'绑定'".我经历了Ninject的这个问题编译错误,但仍不确定如何解决这个问题.如何解决这个问题.如果我能获得代码示例以便我能更好地理解它将会很棒

编辑:

namespace DependencyInjection
{
class Program  
{
    static void Main(string[] args)
    {
        IKernel kernel = new StandardKernel();
        kernel.Bind<IWeapon>().To<Sword>();
        var samurai = kernel.Get<Samurai>(); -----> Exception Line
        samurai.Attack("Hello");
   }       
}

class Samurai
{
    readonly IWeapon _weapon;
    public Samurai(IWeapon weapon)
    {
        _weapon = weapon;
    }
    public void Attack(string target)
    {
        _weapon.Hit(target);
    }
}

interface IWeapon
{
    void Hit(string target);
}

class Sword : IWeapon
{
    public void Hit(string target)
    {
        Console.WriteLine("Sword - ", target);
    }
}

class Arrow : IWeapon
{
    public void Hit(string target)
    {
        Console.WriteLine("Arrow - ", target);
    }
}
}

上面的代码导致行var"samurai = kernel.Get();行上的"MethodAccessException未处理"; 我搜索谷歌,但无法找到任何具体的解决方案

例外

System.MethodAccessException was unhandled
  Message="DependencyInjection.Sword..ctor()"
  Source="Anonymously Hosted DynamicMethods Assembly"
  StackTrace:
       at DynamicInjector84db385a6cfb4301b146100b5027c44a(Object[] )
       at Ninject.Activation.Providers.StandardProvider.Create(IContext context)
       at Ninject.Activation.Context.Resolve()
       at Ninject.KernelBase.<Resolve>b__4(IContext context)
       at System.Linq.Enumerable.<>c__DisplayClass12`3.<CombineSelectors>b__11(TSource x)
       at System.Linq.Enumerable.WhereSelectEnumerableIterator`2.MoveNext()
       at System.Linq.Enumerable.FirstOrDefault[TSource](IEnumerable`1 source)
       at Ninject.Planning.Targets.Target`1.ResolveWithin(IContext parent)
       at Ninject.Activation.Providers.StandardProvider.GetValue(IContext context, ITarget target)
       at Ninject.Activation.Providers.StandardProvider.<>c__DisplayClass1.<Create>b__0(ITarget target)
       at System.Linq.Enumerable.WhereSelectArrayIterator`2.MoveNext()
       at System.Linq.Buffer`1..ctor(IEnumerable`1 source)
       at System.Linq.Enumerable.ToArray[TSource](IEnumerable`1 source)
       at Ninject.Activation.Providers.StandardProvider.Create(IContext context)
       at Ninject.Activation.Context.Resolve()
       at Ninject.KernelBase.<Resolve>b__4(IContext context)
       at System.Linq.Enumerable.<>c__DisplayClass12`3.<CombineSelectors>b__11(TSource x)
       at System.Linq.Enumerable.WhereSelectEnumerableIterator`2.MoveNext()
       at System.Linq.Enumerable.<CastIterator>d__aa`1.MoveNext()
       at System.Linq.Enumerable.FirstOrDefault[TSource](IEnumerable`1 source)
       at Ninject.ResolutionExtensions.Get[T](IResolutionRoot root, IParameter[] parameters)
       at DependencyInjection.Program.Main(String[] args) in D:\Sandboxes\C_Sharp\DependencyInjection\DependencyInjection\Program.cs:line 18
       at System.AppDomain._nExecuteAssembly(Assembly assembly, String[] args)
       at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
       at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
       at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Threading.ThreadHelper.ThreadStart()
  InnerException: 

Answer 1

您收到此错误的原因是因为Bind通常是内核上的方法,因此您应该在模块外部执行此操作.你也应该在解决Samurai之前创建你的绑定,所以交换最后两行:

static void Main(string[] args)
{
    IKernel kernel = new StandardKernel();
    kernel.Bind<IWeapon>().To<Sword>();
    kernel.Bind<Samurai>().ToSelf();
    var samurai = kernel.Get<Samurai>();

}

Bind有时在没有内核的情况下工作的原因是因为你可能在模块中看到了教程.NinjectModule有一个Bind执行相同功能的受保护方法:

public class NinjaModule : NinjectModule {
    public void Load() {
       Bind<Samurai>().ToSelf()
       Bind<IWeapon>().To<Sword>();
    }
} 

这两种方法都是合适的,当你的绑定有点复杂时,建议将它们放入模块中.

编辑确保所有类和接口都是公共的,否则Ninject无法执行它们.如果未指定辅助功能修饰符,则默认为internal.这解释了MethodAccessException.