使用Ninject和MVVM Light

Question

Using MVVM Light in a WPF MVVM application.

I want to use Ninject instead of SimpleIOC.

Even in a brand new WPF/MVVM Light v4 project, I get a null reference for MainViewModel when the Main Property in the ViewModelLocator is called by the XAML.

 private static readonly StandardKernel kernel;

    static ViewModelLocator()
    {
        if (ViewModelBase.IsInDesignModeStatic)
        {
        }
        else
        {
            kernel = new StandardKernel(new mymodule());
        }
    }

    public MainViewModel Main
    {
        get { return kernel.Get<MainViewModel>(); }
    }

MyModule looks like this:

    public class mymodule:NinjectModule
{
    public override void Load()
    {
        Bind<MainViewModel>().ToSelf();
    }
}

I've also tried

    public class mymodule:NinjectModule
{
    public override void Load()
    {
        Bind<MainViewModel>().To<MainViewModel();
    }
}

Answer 1

Ninject kernel's .Get<T> does not return null.

Except in case you explicitly tell it to by doing:

• Bind<T>().ToConstant(null);
• Bind<T>().ToMethod(x => null);
• Bind<T>().ToProvider<TProvider>() --> and TProvider.Create(...) returns null

It's very unlikely you have any of these. So if there's a NullReferenceException when accessing the Main property, it must be because private static readonly StandardKernel kernel is null. Now if the code you've provided us is a Minimal, Complete, and Verifiable example , that means ViewModelBase.IsInDesignModeStatic returns true .