onSignin(form: NgForm){
const UserName = form.value.UserName;
const Password = form.value.Password;
this.authService.signinUser(UserName,Password).map(res => res.json())
 .subscribe(
   data => {
     if (data.Id == 0){
     this.invalid=true;
    }
    else{
      localStorage.setItem('isLoggedin', 'true');
      this.router.navigate(['/calendar']);
      console.log('Ok');
   }})}

signinUser(UserName,Password): Observable<any>{
  return this.http.get('http://api.##.com/api/security/signin?username='+UserName+'&password='+Password);
}