How to inject service into class (not component)

Injections only works with classes that are instantiated by Angulars dependency injection (DI).

1. You need to

• add @Injectable() to MyClass and
• provide MyClass like providers: [MyClass] in a component or NgModule.

When you then inject MyClass somewhere, a MyService instance gets passed to MyClass when it is instantiated by DI (before it is injected the first time).

2. An alternative approach is to configure a custom injector like

With the new static injector

constructor(private injector:Injector) { 
  let childInjector = Injector.create({ providers: [MyClass], parent: this.injector});

  let myClass : MyClass = childInjector.get(MyClass);
}

With the deprecated ReflectiveInjector

constructor(private injector:Injector) { 
  let resolvedProviders = ReflectiveInjector.resolve([MyClass]);
  let childInjector = ReflectiveInjector.fromResolvedProviders(resolvedProviders, this.injector);

  let myClass : MyClass = childInjector.get(MyClass);
}

This way myClass will be a MyClass instance, instantiated by Angulars DI, and myService will be injected to MyClass when instantiated.
See also Getting dependency from Injector manually inside a directive

3. Yet another way is to create the instance yourself:

constructor(ms:myService)
let myClass = new MyClass(ms);