给你的 Factory 和 UnitOfWork 一个泛型类型参数可能是一个解决方案：
public class UnitOfWork<T> : IUnitOfWork<T>
where T : DbContext, new()
{
private T _context;
private readonly IDatabaseFactory<T> _databaseFactory;
protected T Context
{
get { return _context ?? (_context = _databaseFactory.Get()); }
}
public UnitOfWork(IDatabaseFactory<T> factory)
{
_databaseFactory = factory;
_context = _databaseFactory.Get();
}
//More code
}
public class DatabaseFactory<T> : Disposable, IDatabaseFactory<T>
where T : DbContext, new()
{
private T _dataContext;
public T Get()
{
return _dataContext ?? (_dataContext = new T());
}
protected override void DisposeCore()
{
if (_dataContext != null)
_dataContext.Dispose();
}
}
和接口IDatabaseFactory也IUnitWork必须是通用的。
然后，您可以为不同的上下文创建工作单元：
var factory1 = new DatabaseFactory<SiteModelContainer>();
var unitOfWork1 = new UnitOfWork<SiteModelContainer>(factory1);
var factory2 = new DatabaseFactory<AnotherModelContainer>();
var unitOfWork2 = new UnitOfWork<AnotherModelContainer>(factory2);
编辑：
要摆脱服务类中对 EF 的依赖，您可以尝试这样的方法。服务只知道这三个接口：
public interface IUnitOfWorkFactory
{
IUnitOfWork Create(string contextType);
}
public interface IUnitOfWork : IDisposable
{
IRepository<TEntity> CreateGenericRepository<TEntity>()
where TEntity : class;
void Commit();
}
public interface IRepository<T>
{
IQueryable<T> Find(Expression<Func<T, bool>> predicate);
void Attach(T entity);
void Add(T entity);
// etc.
}
以下是特定于 EF 的特殊实现：
public class UnitOfWorkFactory : IUnitOfWorkFactory
{
public IUnitOfWork Create(string contextType)
{
switch (contextType)
{
case "SiteModelContainer":
return new UnitOfWork<SiteModelContainer>();
case "AnotherModelContainer":
return new UnitOfWork<AnotherModelContainer>();
}
throw new ArgumentException("Unknown contextType...");
}
}
public class UnitOfWork<TContext> : IUnitOfWork
where TContext : DbContext, new()
{
private TContext _dbContext;
public UnitOfWork()
{
_dbContext = new TContext();
}
public IRepository<TEntity> CreateGenericRepository<TEntity>()
where TEntity : class
{
return new Repository<TEntity>(_dbContext);
}
public void Commit()
{
_dbContext.SaveChanges();
}
public void Dispose()
{
_dbContext.Dispose();
}
}
public class Repository<T> : IRepository<T>
where T : class
{
private DbContext _dbContext;
private DbSet<T> _dbSet;
public Repository(DbContext dbContext)
{
_dbContext = dbContext;
_dbSet = dbContext.Set<T>();
}
public IQueryable<T> Find(Expression<Func<T, bool>> predicate)
{
return _dbSet.Where(predicate);
}
public void Attach(T entity)
{
_dbSet.Attach(entity);
}
public void Add(T entity)
{
_dbSet.Add(entity);
}
// etc.
}
您的服务将被IUnitOfWorkFactory注入：
public class MyService
{
private IUnitOfWorkFactory _factory;
public MyService(IUnitOfWorkFactory factory)
{
_factory = factory;
}
public MyMethod()
{
using(var unitOfWork1 = _factory.Create("SiteModelContainer"))
{
var repo1 = unitOfWork1.
CreateGenericRepository<SomeEntityTypeInSiteModel>();
// Do some work
unitOfWork1.Commit();
}
using(var unitOfWork2 = _factory.Create("AnotherModelContainer"))
{
var repo2 = unitOfWork2.
CreateGenericRepository<SomeEntityTypeInAnotherModel>();
// Do some work
unitOfWork2.Commit();
}
}
}
当服务被创建时，工厂的具体实例被注入：
var service = new MyService(new UnitOfWorkFactory());
请记住，艰苦的工作将在抽象存储库及其实现中。一旦您的服务类中不再有 EF 上下文，您就必须在 repo 接口中模拟许多方法，以支持所有必要的场景来操作数据。