I'm working around the dependency injection in angular 2.
I had written a sample service which will not contain any constructor
My service :

```
import {Injectable} from '@angular/core'

@Injectable()
export class MyFirstServiceClass{
  //Not working with parameter
  // constructor(nm:string){   
  // }
  SayHello(){
    alert();
      return "Hello, I'm Service...";
  }
}

```

I accessed the service via dependency injection from the constructor as follows :

```
import { Component } from '@angular/core';
import {MyFirstServiceClass} from './MyFirstService.service'

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css']
})
export class AppComponent {
  title = 'app';
  Assignonclick : string;
  constructor(public refsrvc : MyFirstServiceClass){
   this.title = refsrvc.SayHello();
  }
 CallServiceOnBtnClick(){
  this.Assignonclick = this.refsrvc.SayHello();
 }

}

```

It's working if I didnt provide a parameter to the constructor of my service class.
In case I do the following as like providing the parameter in the constructor, I was not able to perform DI.

```
@Injectable()
export class MyFirstServiceClass{
  //Not working with parameter
  constructor(nm:string){   
  }
  SayHello(){
    alert();
      return "Hello, I'm Service...";
  }
}

```

This is providing me the following image straight forward error :

[![enter image description here](https://i.stack.imgur.com/BTfki.png)](https://i.stack.imgur.com/BTfki.png)
How can I perform DI with parameter ?