如何仅使用一个实例来确保InSingletonScope

Question

I want to have only one instance of foo in my code but with this configuration each time it create new instance and I checked every time it comes to constructor and I can't understand why.

public sealed class foo: Ifoo
    {
        public string Test { get; set; }
        public foo()
        {
            this.Test = "test";
        }
    }

my container is like this

public class DefaultNinjectModule : NinjectModule
{
      public override void Load()
    {
         this.Bind<foo>().ToSelf().InSingletonScope();
    }
}

Answer 1

To tell Ninject to Bind the class in a singleton scope:

kernel.Bind<foo>().ToSelf().InSingletonScope();

This behaviour will only work for instances requested from the Kernel .

In your case it is requested by the DefaultNinjectModule( this ) & not the kernel. Create Standard Kernel instance in your DefaultNinjectModule,

var kernel = new StandardKernel();
kernel.Bind<foo>().ToSelf().InSingletonScope();

check this link for reference & customization: Object scopes

Answer 2

You should bind your interface to your class:

public override void Load()
{
    this.Bind<Ifoo>().To<foo>().InSingletonScope();
}

Then when you want foo you use:

kernel.Get<Ifoo>();

This will get you your single instance of foo.

Note: If you have a single instance class derived from IDisposable, you must dispose your single instance, Ninject doesn't do this for you. In your unload do:

public override void Unload()
{
    this.Kernel.Get<Ifoo>().Dispose();
    base.Unload();
}