DAL 数据访问 EF firstcode

//SCHGNContextRepository.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data.Entity;
using System.Linq.Expressions;
using System.Data.SqlClient;

namespace SCHGN.DAL
{
   public class SCHGNContextRepository<T>:IRepository<T> where T :class
    {
        protected DbSet<T> _objectSet;  
        protected SCHGNContext _context;

        public SCHGNContextRepository(SCHGNContext context)  
        {  
            _objectSet = context.Set<T>();  
            _context = context;  
        }
        public SCHGNContextRepository()
        {          
            _context = new SCHGNContext();
            _objectSet = _context.Set<T>();
        }  
        public IQueryable<T> AsQueryable()  
        {  
            return _objectSet;  
        }  
 
        public IEnumerable<T> GetAll()  
        {  
            return _objectSet.ToList();  
        }  
 
        public IEnumerable<T> Find(Expression<Func<T, bool>> where)  
        {  
            return _objectSet.Where(where);  
        }  
 
        public T Single(Expression<Func<T, bool>> where)  
        {  
            return _objectSet.Single(where);  
        }  
 
        public T First(Expression<Func<T, bool>> where)  
        {  
            return _objectSet.First(where);  
        }  
 
        public void Delete(T entity)  
        {  
            if (_context.Entry(entity).State == System.Data.EntityState.Detached)  
                _objectSet.Attach(entity);  
            _objectSet.Remove(entity);  
        }  
 
        public void Add(T entity)  
        {  
            _objectSet.Add(entity);  
        }  
 
        public void Update(T entity)  
        {  
            _objectSet.Attach(entity);  
            _context.Entry(entity).State = System.Data.EntityState.Modified;  
        }
        
        public void Dispose()  
        {  
            System.Diagnostics.Trace.WriteLine("context dispose");  
            _context.Dispose();  
        }

       
    }
}

 

//IRepository.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Linq.Expressions;

namespace SCHGN.DAL
{
    class IRepository<T>:IDisposable where T:class
    {
        IQueryable<T> AsQueryable();
        IEnumerable<T> GetAll();
        IEnumerable<T> Find(Expression<Func<T, bool>> where);
        T Single(Expression<Func<T, bool>> where);
        T First(Expression<Func<T, bool>> where);

        void Delete(T entity);
        void Add(T entity);
        void Update(T entity);  
    }
}