继承从另一个接口派生的接口

Question

下面的代码是派生自 IEmployeeRepository 的 EmployeeRepository class。

 public class EmployeeRepository : IEmployeeRepository
{
    public IEnumerable<Employee> GetEmployeesByGender(string Gender)
    {
        return Context.Employees.Where(emp => emp.Gender == Gender).ToList();
    }

    public IEnumerable<Employee> GetEmployeesByDepartment(string Dept)
    {
        return Context.Employees.Where(emp => emp.Dept == Dept).ToList();
    }  
}

IEmployeeRepository class 如下；

public interface IEmployeeRepository : IGenericRepository<Employee>
{
    IEnumerable<Employee> GetEmployeesByGender(string Gender);
    IEnumerable<Employee> GetEmployeesByDepartment(string Dept);
}

当我构建它时，我得到以下错误以及一些类似的错误；

严重性代码 描述 项目文件行抑制 State 错误 CS0535 'EmployeeRepository' 没有实现接口成员 'IGenericRepository.Delete(Employee)' RepositoryUsingEFinMVC

当我将第一个代码块更改为时，它编译没有错误；

   public class EmployeeRepository : GenericRepository<Employee>, IEmployeeRepository
{
    public EmployeeRepository(IUnitOfWork<EmployeeDBContext> unitOfWork)
        : base(unitOfWork)
    {
    }

    public EmployeeRepository(EmployeeDBContext context)
        : base(context)
    {
    }

    public IEnumerable<Employee> GetEmployeesByGender(string Gender)
    {
        return Context.Employees.Where(emp => emp.Gender == Gender).ToList();
    }

    public IEnumerable<Employee> GetEmployeesByDepartment(string Dept)
    {
        return Context.Employees.Where(emp => emp.Dept == Dept).ToList();
    }

   
}

}

Generic Repository 实现了 IGenericRepository 的所有方法和属性，如下所示；

  public class GenericRepository<T> : IGenericRepository<T>, IDisposable where T : class
{
    private IDbSet<T> _entities;
    private string _errorMessage = string.Empty;
    private bool _isDisposed;

    public GenericRepository(IUnitOfWork<EmployeeDBContext> unitOfWork)
        : this(unitOfWork.Context)
    {
    }

    public GenericRepository(EmployeeDBContext context)
    {
        _isDisposed = false;
        Context = context;
    }

    public EmployeeDBContext Context { get; set; }

    public virtual IQueryable<T> Table
    {
        get { return Entities; }
    }

    protected virtual IDbSet<T> Entities
    {
        get { return _entities ?? (_entities = Context.Set<T>()); }
    }

    public void Dispose()
    {
        if (Context != null)
            Context.Dispose();
        _isDisposed = true;
    }

    public virtual IEnumerable<T> GetAll()
    {
        return Entities.ToList();
    }

    public virtual T GetById(object id)
    {
        return Entities.Find(id);
    }

    public virtual void Insert(T entity)
    {
        try
        {
            if (entity == null)
                throw new ArgumentNullException("entity");
            Entities.Add(entity);

            if (Context == null || _isDisposed)
                Context = new EmployeeDBContext();

            //Context.SaveChanges(); commented out call to SaveChanges as Context save changes will be 
            //called with Unit of work
        }
        catch (DbEntityValidationException dbEx)
        {
            foreach (var validationErrors in dbEx.EntityValidationErrors)
                foreach (var validationError in validationErrors.ValidationErrors)
                    _errorMessage += string.Format("Property: {0} Error: {1}", validationError.PropertyName, validationError.ErrorMessage) + Environment.NewLine;
            throw new Exception(_errorMessage, dbEx);
        }
    }

    public void BulkInsert(IEnumerable<T> entities)
    {
        try
        {
            if (entities == null)
            {
                throw new ArgumentNullException("entities");
            }
            Context.Configuration.AutoDetectChangesEnabled = false;
            Context.Set<T>().AddRange(entities);
            Context.SaveChanges();
        }
        catch (DbEntityValidationException dbEx)
        {

            foreach (var validationErrors in dbEx.EntityValidationErrors)
            {
                foreach (var validationError in validationErrors.ValidationErrors)
                {
                    _errorMessage += string.Format("Property: {0} Error: {1}", validationError.PropertyName,
                                         validationError.ErrorMessage) + Environment.NewLine;
                }
            }
            throw new Exception(_errorMessage, dbEx);
        }
    }

    public virtual void Update(T entity)
    {
        try
        {
            if (entity == null)
                throw new ArgumentNullException("entity");

            if (Context == null || _isDisposed)
                Context = new EmployeeDBContext();

            SetEntryModified(entity);
            //Context.SaveChanges(); commented out call to SaveChanges as Context save changes will be called with Unit of work
        }
        catch (DbEntityValidationException dbEx)
        {
            foreach (var validationErrors in dbEx.EntityValidationErrors)
                foreach (var validationError in validationErrors.ValidationErrors)
                    _errorMessage += Environment.NewLine + string.Format("Property: {0} Error: {1}", validationError.PropertyName, validationError.ErrorMessage);

            throw new Exception(_errorMessage, dbEx);
        }
    }

    public virtual void Delete(T entity)
    {
        try
        {
            if (entity == null)
                throw new ArgumentNullException("entity");

            if (Context == null || _isDisposed)
                Context = new EmployeeDBContext();

            Entities.Remove(entity);
            //Context.SaveChanges(); commented out call to SaveChanges as Context save changes will be called with Unit of work
        }
        catch (DbEntityValidationException dbEx)
        {
            foreach (var validationErrors in dbEx.EntityValidationErrors)
                foreach (var validationError in validationErrors.ValidationErrors)
                    _errorMessage += Environment.NewLine + string.Format("Property: {0} Error: {1}", validationError.PropertyName, validationError.ErrorMessage);
            throw new Exception(_errorMessage, dbEx);
        }
    }

    public virtual void SetEntryModified(T entity)
    {
        Context.Entry(entity).State = EntityState.Modified;
    }
}

所以我的问题是； 1) 为什么我在第一个版本中出现错误？ 2）虽然我没有实现 IGenericRepository 的方法和属性，而只是从派生自 IGenericRepository 的 GenericRepository 派生，但我没有收到任何错误。 为什么？ 3) EmployeeRepository 中使用的以下构造函数的 function 是什么。

public EmployeeRepository(IUnitOfWork<EmployeeDBContext> unitOfWork)
        : base(unitOfWork)
    {
    }

    public EmployeeRepository(EmployeeDBContext context)
        : base(context)
    {
    }

谢谢