EfRepository

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

class EfRepository
{
private DbContext context;

#region 构造函数
public EfRepository(DbContext dbcontext)
{
context = dbcontext;
}
#endregion

#region IRepository

public IQueryable<T> All<T>() where T : class
{
return context.Set<T>().AsNoTracking();
}

public void Update<T>(T entity) where T : class
{
var entry = context.Entry(entity);
if (entry.State == EntityState.Detached)
{
context.Set<T>().Attach(entity);
}
entry.State = EntityState.Modified;
}

public void Insert<T>(T entity) where T : class
{
context.Set<T>().Add(entity);
}

public void Delete<T>(T entity) where T : class
{
var entry = context.Entry(entity);
if (entry.State == EntityState.Detached)
{
context.Set<T>().Attach(entity);
}
entry.State = EntityState.Deleted;
context.Set<T>().Remove(entity);
}

public void Delete<T>(Expression<Func<T, bool>> conditions) where T : class
{
var list = Find<T>(conditions);
foreach (var item in list)
{
Delete<T>(item);
}

}

public T Get<T>(Expression<Func<T, bool>> conditions) where T : class
{
return All<T>().FirstOrDefault(conditions);
}

public List<T> Find<T>(Expression<Func<T, bool>> conditions = null) where T : class
{
if (conditions != null)
{
return All<T>().Where(conditions).ToList();
}
else
{
return All<T>().ToList();
}

}

public List<T> Find<T, S>(Expression<Func<T, bool>> conditions, Expression<Func<T, S>> orderBy, int pageSize, int pageIndex, out int totalCount) where T : class
{
var queryList = conditions == null ?
All<T>() :
All<T>().Where(conditions);

totalCount = queryList.Count();

return queryList.OrderByDescending(orderBy).Skip((pageIndex - 1) * pageSize).Take(pageSize).ToList();
}

public List<T> SqlQuery<T>(string sql)
{
return context.Database.SqlQuery<T>(sql).ToList();
}

public int ExecuteSqlCommand(string sql)
{
return context.Database.ExecuteSqlCommand(sql);
}

public int SaveChanges()
{
return context.SaveChanges();
}

public void Dispose()
{
context.Dispose();
}

public long GetNextSequenceValue(string sequenceName)
{
var rawQuery = context.Database.SqlQuery<long>(string.Format("SELECT NEXT VALUE FOR {0}", sequenceName)).ToList();
long nextVal = rawQuery.Single();
return nextVal;
}

#endregion
}