Strategy Pattern Example

StrategyPatternCSharp

public class MoviesController : Controller
{
    private readonly IMovieRepository _movieRepository;
    public MoviesController(IMovieRepository movieRepository)
    {
        _movieRepository = movieRepository;
    }

    public MoviesController() : this(new EfMovieRepository())
    {}

    // GET: /Movies/
    public ActionResult Index(string movieGenre, string searchString)
    {
        ViewBag.movieGenre = new SelectList(_movieRepository.ListGenres());
        return View(_movieRepository.ListMovies(movieGenre,searchString));
    }
}

public interface IMovieRepository
{
    IEnumerable<string> ListGenres();
    IEnumerable<Movie> ListMovies(string movieGenre, string searchString);
}

public class EfMovieRepository : IMovieRepository
{
    private readonly MovieDbContext db = new MovieDbContext();
    public IEnumerable<string> ListGenres()
    {
        var genreLst = new List<string>();

        var genreQry = from d in db.Movies
                        orderby d.Genre
                        select d.Genre;

        genreLst.AddRange(genreQry.Distinct());

        return genreLst.AsEnumerable();
    }

    public IEnumerable<Movie> ListMovies(string movieGenre, string searchString)
    {
        var movies = from m in db.Movies
                        select m;

        if (!String.IsNullOrEmpty(searchString))
        {
            movies = movies.Where(s => s.Title.Contains(searchString));
        }

        if (!string.IsNullOrEmpty(movieGenre))
        {
            movies = movies.Where(x => x.Genre == movieGenre);
        }
        return movies.AsEnumerable();
    }
}