アプリケーションのEntity Frameworkコンテキストを参照するC＃クラスライブラリ？

Question

私はCodeFirstで生成される独自のデータベーステーブルを使用するクラスライブラリを作成しています。クラスライブラリはモデルを定義し、レコードを追加するにはDbContextが必要です。しかし、コンパイル時にアプリケーションがdbコンテキストを持っていることを知らなくても、どうすればいいのですか？

アプリケーションが自分デシベルコンテキストにこの行を追加する必要があります：

public DbSet<MyClassLibraryRecords> MyClassLibraryRecords { get; set; } 

が、その後、彼は私がapp_context.MyClassLibraryRecords.Add(record);を行うにはMyClassLibraryRecordsにアクセスできるように何とかクラスライブラリへのアプリケーションデシベルのコンテキストを与えるために必要ですか？

コールバックメソッドを使用するか、アプリケーションがデータベースに実際に格納するためにオーバーライドするメソッドを使用する必要がありますか？私はむしろクラスライブラリですべてをやることができればもっと簡単になるでしょう...

Answer 1

独自のDBContextを構築する必要があります。そのため、エンティティフレームワークはドメインの一部であるクラスを認識します。

CREATE TABLE [dbo].[account](
     [account_id] [int] IDENTITY(1,1) NOT NULL, 
     [name] [nvarchar](50) NOT NULL, 
    CONSTRAINT [PK_dbo.account] PRIMARY KEY CLUSTERED 
    (
     [account_id] ASC 
    )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] 
    ) ON [PRIMARY] 

    GO 


    CREATE TABLE [dbo].[address](
     [address_id] [int] IDENTITY(1,1) NOT NULL, 
     [account_id] [int] NOT NULL, 
     [full_address] [nvarchar](256) NOT NULL, 
    CONSTRAINT [PK_dbo.address] PRIMARY KEY CLUSTERED 
    (
     [address_id] ASC 
    )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] 
    ) ON [PRIMARY] 

    GO 

    ALTER TABLE [dbo].[address] WITH CHECK ADD CONSTRAINT [FK_dbo.address_dbo.account_account_id] FOREIGN KEY([account_id]) 
    REFERENCES [dbo].[account] ([account_id]) 

------------------------------------------------------- 

db connection string 
    <add name="accountDB" connectionString="data source=.; initial catalog=test; integrated security=true;" providerName="System.Data.SqlClient" /> 

--------------------------------------------------- 


    using System; 
using System.Collections; 
using System.Collections.Generic; 
using System.Threading; 
using System.Threading.Tasks; 
using System.Linq; 
using System.Data.Entity; 
using System.Data.Entity.ModelConfiguration; 





/// <summary> 
/// Define my domain. 
/// </summary> 
public class Account 
{ 
    public Account() 
    { 
     this.Addresses = new List<Address>(); 
    } 
    public int? AccountID { get; set; } 
    public string Name { get; set; } 
    public virtual ICollection<Address> Addresses { get; set; } 
} 
public class Address 
{ 
    public int? AddressID { get; set; } 
    public int AccountID { get; set; } 
    public string FullAddress { get; set; } 
} 
public interface IAccountService 
{ 
    Account GetAccount(int accountID); 
    void SaveAccount(Account account); 
} 
public interface IAccountRepository 
{ 
    IQueryable<Account> GetAccounts(); 
    void UpdateAccount(Account account); 
    void CreateAccount(Account account); 
} 
public class AccountService : IAccountService 
{ 
    private IAccountRepository _repository; 
    public AccountService(IAccountRepository repository) 
    { 
     this._repository = repository; 
    } 
    public Account GetAccount(int accountID) 
    { 
     //you can do some validation. for ex) if we pass the user's name, we can see if they have access rights to the system, module, and data 
     return (from acc in this._repository.GetAccounts().AsNoTracking() 
       where acc.AccountID == accountID 
       select acc).FirstOrDefault(); 
    } 
    public void SaveAccount(Account account) 
    { 
     //apply your business rules such as validating the data, user access rights, and etc 
     if (account.AccountID.HasValue) 
     { 
      this._repository.UpdateAccount(account); 
     } 
     else 
     { 
      this._repository.CreateAccount(account); 
     } 
    } 
} 




/// <summary> 
/// Data access layer. 
/// 
/// This layer knows about your data saource such as sql server, oracle, or mongoDB. 
/// </summary> 
public class AccountConfig : EntityTypeConfiguration<Account> 
{ 
    public AccountConfig() : base() 
    { 
     this.ToTable("account", "dbo") 
      .HasKey(p => p.AccountID); 

     this.Property(p => p.AccountID) 
      .HasColumnName("account_id") 
      .HasDatabaseGeneratedOption(System.ComponentModel.DataAnnotations.Schema.DatabaseGeneratedOption.Identity); 

     this.Property(p => p.Name) 
      .HasColumnName("name") 
      .HasColumnType("nvarchar") 
      .HasMaxLength(50) 
      .IsRequired(); 

     //define the relationship between account and address 
     this.HasMany(p => p.Addresses).WithRequired().HasForeignKey(p => p.AccountID).WillCascadeOnDelete(false); 
    } 
} 
public class AddressConfig : EntityTypeConfiguration<Address> 
{ 
    public AddressConfig() : base() 
    { 
     this.ToTable("address", "dbo") 
      .HasKey(p => p.AddressID); 

     this.Property(p => p.AddressID) 
      .HasColumnName("address_id") 
      .HasDatabaseGeneratedOption(System.ComponentModel.DataAnnotations.Schema.DatabaseGeneratedOption.Identity); 

     this.Property(p => p.AccountID) 
      .HasColumnName("account_id") 
      .IsRequired(); 

     this.Property(p => p.FullAddress) 
      .HasColumnName("full_address") 
      .HasColumnType("nvarchar") 
      .HasMaxLength(256) 
      .IsRequired(); 
    } 
} 
public class AccountDBContext : DbContext 
{ 
    public AccountDBContext() : this("accountDB") { } 
    public AccountDBContext(string nameOrConnectionString) : base(nameOrConnectionString) 
    { 
     //I dont want to use any database initialization i.e create database if it doesnt exist 
     //since your dev shop will have a deployment process, get use to the process of generating deployment scripts. 
     Database.SetInitializer<AccountDBContext>(null); 
     this.Configuration.ProxyCreationEnabled = false; 
     this.Configuration.LazyLoadingEnabled = false; 
    } 

    public IDbSet<Account> Accounts { get; set; } 

    protected override void OnModelCreating(DbModelBuilder modelBuilder) 
    { 
     //map the domain types to the database tables using your database naming convention. 
     modelBuilder.Configurations.Add(new AddressConfig()); 
     modelBuilder.Configurations.Add(new AccountConfig()); 
    } 
} 

//repository is on the data access layer, because it's coupled to EF and the context object. 
public class AccountRepository : IAccountRepository 
{ 
    private AccountDBContext _context; 
    public AccountRepository() 
    { 
     this._context = new AccountDBContext(); 
    } 
    public AccountRepository(string nameOrConnectionString) 
    { 
     this._context = new AccountDBContext(nameOrConnectionString); 
    } 

    public IQueryable<Account> GetAccounts() 
    { 
     return this._context.Accounts 
         .AsNoTracking() 
         .Include("Addresses"); 
    } 

    public void CreateAccount(Account account) 
    { 
     this._context.Entry(account).State = EntityState.Added; 
     this._context.SaveChanges(); 
    } 

    public void UpdateAccount(Account account) 
    { 
     var temp = (from acc in this.GetAccounts() 
        where acc.AccountID == account.AccountID 
        select acc).First(); 

     temp.Name = account.Name; 

     //sync address... we'll just add for brevity sake. 
     if (account.Addresses != null) 
     { 
      foreach (var addr in account.Addresses) 
      { 
       if (!addr.AddressID.HasValue) 
       { 
        this._context.Entry(addr).State = EntityState.Added; 
       } 
      } 
     } 

     this._context.SaveChanges(); 
    } 
} 






public class Program 
{ 
    public static void Main() 
    { 
     try 
     { 
      IAccountService service = new AccountService(new AccountRepository()); 

      //create new 
      var account = new Account() 
      { 
       Name = "john doe" 
      }; 
      account.Addresses.Add(new Address() 
      { 
       FullAddress = "San Fran, CA" 
      }); 
      account.Addresses.Add(new Address() 
      { 
       FullAddress = "Texas" 
      }); 
      service.SaveAccount(account); 





      //get the account. I know the first accountID is one. I checked the database for testing. 
      ; 
      var savedAccount = service.GetAccount(1); 

      //lets update it 
      savedAccount.Name = "J. Doe"; 
      savedAccount.Addresses.Add(new Address() 
      { 
       AccountID = savedAccount.AccountID.Value, 
       FullAddress = "Conn" 
      }); 

      service.SaveAccount(savedAccount); 
     } 
     catch (Exception ex) 
     { 
      Console.WriteLine(ex.Message); 
     } 
    } 

} 

本当にエンティティフレームワークを読む必要があります。トランザクション、並行性、複雑なオブジェクトグラフ、パターンなどのトピックについては話しませんでした。