如何使用UnitOfWork和DatabaseFactory & Generic Repository添加多DbContext

Question

我想在我的 ASP.NET MVC 5 应用程序中添加两个 DbContext，一个用于 ASPIdentity 的 DbContext，另一个用于我的应用程序数据库。我正在使用存储库模式。m y 问题是，如何在 BaseRepository 中指定每个 DbContext 的实体？这是我所做的。

1- DatabaseFactory & IDatabaseFactory

public class DatabaseFactory<T> where T : DbContext,new() 
{
    private T dbContext;
    public T Init()
    {
        return dbContext ?? (dbContext = new T());
    }
}

public interface IDatabaseFactory<T> where T : DbContext
{
    T Init();
}

2- IUnitOfWork & UnitOfWork

public class UnitOfWork<T> : IUnitOfWork<T> where T : DbContext
{
    private readonly IDatabaseFactory<T> dbFactory;
    private T dbContext;
    public UnitOfWork(IDatabaseFactory<T> dbFactory)
    {
        this.dbFactory = dbFactory;
    }
    protected T DbContext
    {
        get { return dbContext ?? (dbContext = dbFactory.Init()); }
    }
    public void Commit()
    {
        DbContext.SaveChanges();
    }
}
public interface IUnitOfWork<T> where T : DbContext, IDisposable
{
    void Commit();
}

3-基本存储库.cs

public abstract class BaseRepository<T> where T : class
{
    #region Properties
    private DbContext dataContext;
    private readonly IDbSet<T> dbSet;
    protected IDatabaseFactory DbFactory
    {
        get;
        private set;
    }
    protected DbContext dbContext
    {
        get { return dataContext ?? (dataContext = DbFactory.Init()); }
    }
    #endregion
    protected BaseRepository(IDatabaseFactory dbFactory)
    {
        this.DbFactory = dbFactory;
        this.dbSet = this.DbContext.Set<T>();
    }
    #region Implementation
    public virtual void Add(T entity)
    {
        dbSet.Add(entity);
    }
    public virtual void Update(T entity)
    {
        dbSet.Attach(entity);
        dataContext.Entry(entity).State = EntityState.Modified;
    }
    public virtual void Delete(T entity)
    {
        dbSet.Remove(entity);
    }
    public virtual void Delete(Expression<Func<T, bool>> where)
    {
        IEnumerable<T> objects = dbSet.Where<T>(where).AsEnumerable();
        foreach (T obj in objects)
            dbSet.Remove(obj);
    }
    public virtual T GetById(int id)
    {
        return dbSet.Find(id);
    }
    public virtual IEnumerable<T> GetAll()
    {
        return dbSet.ToList();
    }
    public virtual IEnumerable<T> GetMany(Expression<Func<T, bool>> where)
    {
        return dbSet.Where(where).ToList();
    }
    public T Get(Expression<Func<T, bool>> where)
    {
        return dbSet.Where(where).FirstOrDefault<T>();
    }
    #endregion
}

Answer 1

我也在尝试实现通用存储库模式，但没有 UOW。
要创建两个 DbContext，您应该在基本存储库中再添加一个类型。
此外，DbFactory 的创建逻辑应该只在 UOW 中，而不是在 BaseRepository 中。
下面是为您提供的简化代码。并更具体地说明您尝试过的内容。

2- IUnitOfWork & UnitOfWork

public class UnitOfWork<T1, T2> : IUnitOfWork<T1, T2> where T1 : DbContext where T2 : DbContext {
      // FOr DbFactories
      private readonly IDatabaseFactory<T1> _dbFactory1;
      private readonly IDatabaseFactory<T2> _dbFactory2;
      //For Seperate DbContexes
      private T _dbContext1;
      private T _dbContext2;
      public UnitOfWork () {
        _dbFactory1 = new DatabaseFactory<T1> ();
        _dbFactory2 = new DatabaseFactory<T2> ();
      }
      //For Accessiong DbContext Objects in Base Repository
      protected T DbContext1 {
        get { return _dbContext1 ?? (_dbContext1 = _dbFactory1.Init ()); }
      }
      protected T DbContext2 {
        get { return _dbContext2 ?? (_dbContext2 = _dbFactory2.Init ()); }
      }
      public void Commit () {
        DbContext1.SaveChanges ();
        DbContext2.SaveChanges ();
      }
    }
    public interface IUnitOfWork<T1, T2> where T1 : DbContext where T2 : DbContext, IDisposable {
      void Commit ();
    }
}

3 - 基本存储库和示例

public abstract class BaseRepository<T1,T2,T> : IUnitOfWork<T1, T2> where T : class where T1 : DbContext where T2 : DbContext {
  #region Properties
  // private DbContext _dataContext1; //for first DbContext
  // private DbContext _dataContext1; //for second DbContext
  private readonly IDbSet<T> _dbSet1; //Going to Perform Operations using Dbsets
  private readonly IDbSet<T> _dbSet2;
//For Exposing DbContext to respective Implementing Repositories This is Optional
  protected DbContext DataContext1 {
    get { return DbContext1; } //retuning DbCOntext Object Created in UOW class
  }
  protected DbContext DataContext2 {
    get { return DbContext2; }
  }
  //For Exposing DbSets to respective Implementing Repositories This is Optional
  protected IDbSet<T> DbSet1 => _dbSet1;
  protected IDbSet<T> DbSet2 => _dbSet2;
  protected BaseRepository () {
    _dbSet1 = DataContext1.Set<T> ();
    //OR
    _dbSet2 = DataContext2.Set<T> ();
  }
  #endregion
  #region Implementation
  #endregion
}

//SPecific Repository Example using Person Class
public class PersonRepository:BaseRepository<AspIdentityDbContext,AppDbContext,Person> {
  //can use DbContexes from BaseRepository to write Additional Methods/Queries On dbSets
}

试试这个并提供反馈。