Select data using Entity Framework based on advanced search options

Question

I have a project that uses EF to interact with a database. He does this through the WCF web service. This is my first EF project, and I'm trying to figure out how to build a query based on optional parameters.

My web service has a contract with the corresponding fields for classes in EF. The web service processes the database, populates these client classes, and passes them back to the client. For example...

In web service

[DataContract]
public class MyMovie
{
    [DataMember]
    public int MovieId;
    [DataMember]
    public string MovieName;
    [DataMember]
    public int MovieRatingId;
    [DataMember]
    public string MovieRunTime;
    [DataMember]
    public string MovieIMDBUrl;
    [DataMember]
    public DateTime MovieDateAdded;
    [DataMember]
    public List<MyMovieActor> Actors;
    [DataMember]
    public List<MyMovieMedia> MediaFiles;
}
public class MyMovieActor
{
    [DataMember]
    public int ActorId;
    [DataMember]
    public int ActorMovieId;
    [DataMember]
    public string ActorName;
    [DataMember]
    public string ActorCharacter;
}
public class MyMovieMedia
{
    [DataMember]
    public int MediaId;
    [DataMember]
    public int MediaMovieId;
    [DataMember]
    public string MediaFileLocation;
    [DataMember]
    public bool MediaDefault;
}

Data Model (Simplified) ...

My web service method ....

    public MyMovie GetMovie(int movieId)
    {
        MyMovie response = new MyMovie();

        using (MovieDatabaseEntities DbContext = new MovieDatabaseEntities())
        {
            var query = (from oData in DbContext.Movies
                         where oData.MovieId == movieId
                         select oData).ToList();


            if (query.Count > 0)
            {
                response.MovieDateAdded = query[0].MovieDateAdded;
                response.MovieId = query[0].MovieId;
                response.MovieIMDBUrl = query[0].MovieIMDBUrl;
                response.MovieName = query[0].MovieName;
                response.MovieRatingId = query[0].MovieRatingId;
                response.MovieRunTime = query[0].MovieRunTime;
            }

            List<MyMovieActor> actors = new List<MyMovieActor>();
            foreach (MovieActor ma in query[0].MovieActors)
            {
                MyMovieActor a = new MyMovieActor();
                a.ActorId = ma.ActorId;
                a.ActorMovieId = ma.ActorMovieId;
                a.ActorCharacter = ma.ActorCharacter;
                a.ActorName = ma.ActorName;
                actors.Add(a);
            }
            response.Actors = actors;

            List<MyMovieMedia> medias = new List<MyMovieMedia>();
            foreach (MovieMedia mm in query[0].MovieMedias)
            {
                MyMovieMedia med = new MyMovieMedia();
                med.MediaId = mm.MediaId;
                med.MediaMovieId = mm.MediaMovieId;
                med.MediaFileLocation = mm.MediaFileLocation;  //HDD Folder 
                med.MediaDefault = mm.MediaDefault; //Image to show on listing
                medias.Add(med);
            }
            response.MediaFiles = medias;
        }
        return response;
    }

So now I want to create

public List<MyMovie> GetMovies(string moviename, int movierating, string movieruntime)

Where all parameters or lines with zero length will be filled. If they have values, I want to add this as part of the where clause.

so basically update

                var query = (from oData in DbContext.Movies
                         where oData.MovieId == movieId
                         select oData).ToList();

to equivalent

            var query = (from oData in DbContext.Movies
                         where 1=1
                   if(String.IsSafe(moviename))
                   {
                         && oData.MovieName Like %movieId%
                   }
                   if(movierating != 0)
                   {
                         && oData.MovieRating = movierating
                   }
                   if(String.IsSafe(movieruntime))
                   {
                         && oData.MovieRuntime == movieruntime
                   }
                         select oData).ToList();

, , ADO.NET, DataReaders, Adapters, Stored Procs .., EF. . ?!

.

Answer 1

IQueryable - . , SQL , (, - ToList()). , :

var query = (from oData in DbContext.Movies select oData);
if (!string.IsNullOrEmpty(moviename))
  query = query.Where(m => m.MovieName.Contains(moviename));
...