How to return a query based on linq when using a task windows phone 8.1

Question

I am new to tasks and I am trying to figure out how to do a query on a list that is returned from aync method usually I would do something like this cause obv linq is not a async method how would one achieve this kinda of secenrio

List<MovieDetail> _mySearchDetail = _myMovie.Where(p => p.name == movietitle).ToList();

But cause its retunning from a task that wont work my two methods are as follows.

This gets the movie details from the webservice

public async Task<List<MovieDetail>> GetMovieDetailsList(int movieId)
{

        var tcs = new TaskCompletionSource<List<MovieDetail>>();
        string jsonresult = await WCFRESTServiceCall("GET", "movie_details");

        var list = await Task.Run(() => jsonresult.Deserialize<MovieDetails>());
        tcs.SetResult(list.movieDetaillist);
        // for testing to show json being returned
        var dialog = new MessageDialog(jsonresult);
        await dialog.ShowAsync();

        return await tcs.Task;
}

Then what I was wanting to do was build up a search function to allow me to search movie by name , description , actor and what not.

public Task<List<MovieDetail>> searchMovies(string movietitle)
{
        List <MovieDetail> _myMovie = await GetMovieDetailsList(1);
        var list = await Task.Run(() => how do i query above here ???? >());


        List<MovieDetail> _mySearchDetail = _myMovie.Where(p => p.name == movietitle).ToList();

        return await tcs.Task;
}

I have included my movieDetail class for completness of code:

public class MovieDetail
{
    public string id { get; set; }
    public string name { get; set; }
    public string description { get; set; }
    public string image { get; set; }
    public string secondry_images { get; set; }
    public string actor { get; set; }
    public string actoress { get; set; }
    public string director { get; set; }
    public string music_director { get; set; }
    public string release_date { get; set; }
    public string tags { get; set; }
    public string age_restriction { get; set; }
    public string box_office { get; set; }
    public string official_site { get; set; }
    public string duration { get; set; }
    public string writers { get; set; }
    public int imdb { get; set; }
    public string status { get; set; }
    public string language { get; set; }
    public string created { get; set; }
    public string modified { get; set; }
    public string movie_category_id { get; set; }
    public string slug { get; set; }
    public string movie_show_time_id { get; set; }
    public string theatre_movie_screen_id { get; set; }
    public string videous { get; set; }
    public string videos { get; set; }
    public string comming_soon { get; set; }
    public string avg { get; set; }
}

 public class MovieDetails
{
    public List<MovieDetail> movieDetaillist { get; set; } 
}

Wosi · Accepted Answer · 2015-08-13T22:41:03.220

1

Why do you use a TaskCompletionSource in GetMovieDetailsList?

I'd do it like this:

public async Task<List<MovieDetail>> GetMovieDetailsList(int movieId)
{   
        string jsonresult = await WCFRESTServiceCall("GET", "movie_details");    
        var list = jsonresult.Deserialize<MovieDetails>();
        return list.movieDetaillist;
}

Your searchMovies method can look like this:

public async Task<List<MovieDetail>> searchMovies(string movietitle)
{
        List <MovieDetail> _myMovie = await GetMovieDetailsList(1);
        var list = _myMovie.Where(p => p.name == movietitle).ToList();    
        return list;
}

await the time expensive things. It doesn't matter how you got the list. You forget about that the list was built in a task after you get it. You can query it just like you do it with every other list.

edited Aug 13 '15 at 22:41

answered Aug 13 '15 at 22:33

Wosi

41,986
17
75
82

thanks that worked I am just getting used to making web service calls so that was the example i came across – c-sharp-and-swiftui-devni Aug 13 '15 at 22:37
with the linq how would I build a query of optional where cluases can i do that with linq ? – c-sharp-and-swiftui-devni Aug 13 '15 at 22:39
That's a new question. You should read some Linq tutorials or at least http://stackoverflow.com/questions/2101540/linq-or-equivalent-of-where – Wosi Aug 13 '15 at 22:43

score 0 · Answer 2 · answered Aug 13 '15 at 22:35

In your, after the first awaited call, you have the result, so you can do

public Task<List<MovieDetail>> searchMovies(string movietitle)
{
        List <MovieDetail> _myMovie = await GetMovieDetailsList(1);
        var list = await Task.Run(() => how do i query above here ???? >());


        List<MovieDetail> _mySearchDetail = _myMovie.Where(p => p.name == movietitle).ToList();
            return await tcs.Task;
}


_myMovie.Where(x => x.Name == "title");

Or any property you want to search with

How to return a query based on linq when using a task windows phone 8.1

2 Answers2