次のメソッドでパラメータとしてIQueryableを取得するにはどうすればよいですか？

Question

私は私のコードをより良くするためにみますと、私は次の関数に

エラーのIQueryableを取得する方法を知らない：

An exception of type 'System.InvalidOperationException' occurred in EntityFramework.dll but was not handled in user code

Additional information: The operation cannot be completed because the DbContext has been disposed.

これが問題である：

public List<GitUser> FavoritesUsersListFromHistory(IQueryable users) 
    { 
     List<GitUser> favoritesList = new List<GitUser>(); 
     using (var db = new GitContext()) 
     { 
      foreach (CookiesHistory result in users) <-- users make this error 
      { 
       var user = (from u in db.GitUsers 
          where u.Id == result.GitUserId 
          select new { u }).First(); 

       favoritesList.Add(user.u); 
      } 
     } 
     return favoritesList; 

これは、前のコードです変更：

  List<GitUser> favoritesList = new List<GitUser>(); 


     using (var db = new GitContext()) 
     { 
      var results = (from ch in db.CookiesHistory 
          where ch.GitUserId != null 
          where ch.MyCookieId == cookieId 
          group ch by new { ch.GitUserId, ch.MyCookieId, ch.SearchGitUser } into g 
          orderby g.Count() descending 
          select new { GitUserId = g.Key.GitUserId, MyCookieId = g.Key.MyCookieId, SearchGitUser = g.Key.SearchGitUser, Count = g.Count() }).Take(count); 


      foreach (var result in results) 
      { 
       var user = (from u in db.GitUsers 
          where u.Id == result.GitUserId 
          select new { u }).First(); 

       favoritesList.Add(user.u); 
      } 

      return favoritesList; 

変更後のコード：

public FavoritesController(IGitUserRepository repo, CookieHelper _cookieHelper) 
    { 
     //myCookieRepository = cookieRepo;IMyCookieRepository cookieRepo, 
     repository = repo; 
     cookieHelper = _cookieHelper; 
    } 




    // GET: Favorites 
    public PartialViewResult FavoritesRepos() 
    { 
     IEnumerable<GitUser> favorites = FavoritesUsers(cookieHelper.GetHttpCookieId(), countOfFavoritesUsers); 
     return PartialView("_FavoritesRepos", favorites); 
    } 



    public IEnumerable<GitUser> FavoritesUsers(int cookieId, int count) 
    { 
      return FavoritesUsersListFromHistory(TopFavoritesUsers(cookieId, count)); 
    } 

    public IQueryable TopFavoritesUsers(int cookieId, int count) 
    { 
     using (var db = new GitContext()) 
     { 
      IQueryable results = (from ch in db.CookiesHistory 
          where ch.GitUserId != null 
          where ch.MyCookieId == cookieId 
          group ch by new { ch.GitUserId, ch.MyCookieId, ch.SearchGitUser } into g 
          orderby g.Count() descending 
          select new { GitUserId = g.Key.GitUserId, MyCookieId = g.Key.MyCookieId, SearchGitUser = g.Key.SearchGitUser, Count = g.Count() }).Take(count); 
      return results; 
     } 
    } 

    public List<GitUser> FavoritesUsersListFromHistory(IQueryable users) 
    { 
     List<GitUser> favoritesList = new List<GitUser>(); 
     using (var db = new GitContext()) 
     { 
      foreach (CookiesHistory result in users) 
      { 
       var user = (from u in db.GitUsers 
          where u.Id == result.GitUserId 
          select new { u }).First(); 

       favoritesList.Add(user.u); 
      } 
     } 
     return favoritesList; 
    } 

Answer 1

まず、エラーは、パラメータとして渡すクエリを作成するために使用するコンテキストが、結果を反復しようとしたときに破棄されていることです。だから私の最初の勧告は、あなたのコンテキスト変数をグローバル変数として作成することです：

public class FavoriteController 
{ 
    protected GitContext db; 
    public FavoriteController() 
    { 
    db=new GitContext(); 
    } 

    public IEnumerable<GitUser> FavoritesUsers(int cookieId, int count) 
    { 
     return FavoritesUsersListFromHistory(TopFavoritesUsers(cookieId, count)); 
    } 

    //create a class (CookiesHistoryDTO) to save the result of this query 
    public IQueryable<CookiesHistoryDTO> TopFavoritesUsers(int cookieId, int count) 
    { 

     IQueryable<CookiesHistoryDTO> results = (from ch in db.CookiesHistory 
               where ch.GitUserId != null 
               where ch.MyCookieId == cookieId 
               group ch by new { ch.GitUserId, ch.MyCookieId, ch.SearchGitUser } into g 
               orderby g.Count() descending 
               select new CookiesHistoryDTO{ GitUserId = g.Key.GitUserId, MyCookieId = g.Key.MyCookieId, SearchGitUser = g.Key.SearchGitUser, Count = g.Count() } 
              ).Take(count); 
     return results; 

    } 


    public IEnumerable<GitUser> FavoritesUsersListFromHistory(IQueryable<CookiesHistoryDTO> user) 
    { 
    //Here the context you use to create your first query is still alive 
    var userIds=user.Select(e=>e.GitUserId).Contains(e.Id); 
    return db.GitUsers.Where(e=>userIds.Contains(e.Id)).ToList();// Here is when both query are going to be executed. 
    } 

    protected override void Dispose(bool disposing) 
    { 
    if (disposing) 
    { 
     db.Dispose(); 
    } 
    base.Dispose(disposing); 
    } 
}