c# - 単一のオブジェクトとリストの両方について、1つのオブジェクトをanotheに変換するための最小のコード

Question

I need to convert one object to another...in both cases of a single instance of the object as well as corresponding Lists of those objects. I'd rather not have to perform the same mappings in 2 places. Here is what I mean: This converts a Facebook movie to a Standard Movie object

//Converts an Facebook object to a Standard Movie object
    public MovieDetails ConvertFacebookMovieToStandardMovie(FacebookMovie Movies)
    {
        MovieDetails objMovieDetails = new MovieDetails();
        objMovieDetails.ID = 0;
        objMovieDetails.Source = Movies.Source;
        objMovieDetails.SourceID = Convert.ToString(Movies.ID);
        objMovieDetails.Title = Movies.Name;
        objMovieDetails.URL = GetInternalMovieURL(objMovieDetails.Source, objMovieDetails.SourceID);
        objMovieDetails.ImageURL = Movies.Picture;
        objMovieDetails.SourceURL = Movies.SourceURL;
        objMovieDetails.Description = Movies.Description

        return objMovieDetails;

    }//Convert Facebook to standard

Now I also need to do the same things in cases where I have the same objects, just in List form, i.e.

//Converts an Facebook class to a MovieDetails class of WWN
    public List<MovieDetails> ConvertFacebookMovieToStandardMovie(List<FacebookMovie> lstFacebookMovieDetails)
    {
        List<MovieDetails> lstMovieListDetails = lstFacebookMovieDetails.Select(Movies => new MovieDetails()
        {
            ID = 0
            ,Source = Movies.Source
            ,SourceID = Convert.ToString(Movies.ID)
            ,Title = Movies.Name
            ,URL = GetInternalMovieURL(Source, SourceID)
            ,ImageURL = Movies.Picture
            ,SourceURL = Movies.SourceURL
            ,Description = Movies.Description
        }).ToList();

        return lstMovieListDetails;

    }//Convert Facebook to standard

I'm new to c# and linq, so not sure how I could create one method that could handle both...or at least a way to encapsulate the mappings.

I know I could create an overload method for the List scenario and loop through the items in the list and call the first object convert method...But I was hoping to use the linq route I currently have for, what I'm guessing, is better performance.

Thanks! Chad

score 2 · Accepted Answer

関数を呼び出すだけです。

 public List<MovieDetails> ConvertFacebookMovieToStandardMovie(List<FacebookMovie> lstFacebookMovieDetails)
    {
        List<MovieDetails> lstMovieListDetails =
          lstFacebookMovieDetails.Select(Movies => ConvertFacebookMovieToStandardMovie(Movies)).ToList();

        return lstMovieListDetails;
     }

または他の方法

public MovieDetails ConvertFacebookMovieToStandardMovie(FacebookMovie Movies)
{
    return ConvertFacebookMovieToStandardMovie(new [] { Movies} ).FirstOrDefault();
}//Convert Facebook to standard

asその後、オーバーロードすることもできます

public static MovieDetails operator as(FacebookMovie m)
{
   if (m == null) return null;

    MovieDetails objMovieDetails = new MovieDetails()
        {
          ID = 0,
          Source = Movies.Source,
          SourceID = Convert.ToString(Movies.ID),
          Title = Movies.Name,
          URL = GetInternalMovieURL(objMovieDetails.Source, objMovieDetails.SourceID),
          ImageURL = Movies.Picture,
          SourceURL = Movies.SourceURL,
          Description = Movies.Description
       }

    return objMovieDetails
}

ConvertFacebookMovieToStandardMovie はばかげているように見えますが、次のようになります。

public MovieDetails ConvertFacebookMovieToStandardMovie(FacebookMovie Movies)
{
    return Movies as MovieDetails;
}//Convert Facebook to standard

と

public List<MovieDetails> ConvertFacebookMovieToStandardMovie(List<FacebookMovie> lstFacebookMovieDetails)
{
    List<MovieDetails> lstMovieListDetails = 
      lstFacebookMovieDetails.Select(Movies => Movies as MovieDetails).ToList();

    return lstMovieListDetails;

}

score 1 · Accepted Answer

Unless there's a performance gain on having separate code for these two cases I'd simply scrap the single movie variant and keep the List variant. To do the single movie variant simply do this with using System.Linq;:

List<FacebookMovie> moviesDetailsList = ...
MovieDetails movieDetails = ConvertFacebookMovieToStandardMovie(moviesDetailsList).Single();

If you want the single case as a separate method, you can place the above as the body of that method with "..." = new [] {movieDetail};

score 0 · Accepted Answer

A shorter version

 public List<MovieDetails> ConvertFacebookMovieToStandardMovie(List<FacebookMovie> lstFacebookMovieDetails)
{
    return lstFacebookMovieDetails.ConvertAll(ConvertFacebookMovieToStandardMovie);
 }

As per msdn

Converts the elements in the current List to another type, and returns a list containing the converted elements.

3 に答える 3

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