EF帮助类

public class BaseService
{
#region Identity
protected DbContext Context = new Model.TestEntities();
/// <summary>
/// 构造函数注入
/// </summary>
/// <param name="context"></param>
//public BaseService(DbContext context)
//{
// this.Context = context;
//}
#endregion Identity

#region Query
public T Find<T>(int id) where T : class
{
return this.Context.Set<T>().Find(id);
}

/// <summary>
/// 不应该暴露给上端使用者，尽量少用
/// </summary>
/// <typeparam name="T"></typeparam>
/// <returns></returns>
[Obsolete("尽量避免使用，using 带表达式目录树的代替")]
public IQueryable<T> Set<T>() where T : class
{
return this.Context.Set<T>();
}

/// <summary>
/// 这才是合理的做法，上端给条件，这里查询
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="funcWhere"></param>
/// <returns></returns>
public IQueryable<T> Query<T>(Expression<Func<T, bool>> funcWhere) where T : class
{
if (funcWhere == null)
return this.Context.Set<T>();
else
return this.Context.Set<T>().Where<T>(funcWhere);
}

public PageResult<T> QueryPage<T, S>(Expression<Func<T, bool>> funcWhere, int pageSize, int pageIndex, Expression<Func<T, S>> funcOrderby, bool isAsc = true) where T : class
{
var list = this.Set<T>();
if (funcWhere != null)
{
list = list.Where<T>(funcWhere);
}
if (isAsc)
{
list = list.OrderBy(funcOrderby);
}
else
{
list = list.OrderByDescending(funcOrderby);
}
PageResult<T> result = new PageResult<T>()
{
DataList = list.Skip((pageIndex - 1) * pageSize).Take(pageSize).ToList(),
PageIndex = pageIndex,
PageSize = pageSize,
TotalCount = list.Count()
};
return result;
}
#endregion

#region Insert
/// <summary>
/// 即使保存 不需要再Commit
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="t"></param>
/// <returns></returns>
public T Insert<T>(T t) where T : class
{
this.Context.Set<T>().Add(t);
this.Commit();//写在这里 就不需要单独commit 不写就需要
return t;
}

public IEnumerable<T> Insert<T>(IEnumerable<T> tList) where T : class
{
this.Context.Set<T>().AddRange(tList);
this.Commit();//一个链接 多个sql
return tList;
}
#endregion

#region Update
/// <summary>
/// 是没有实现查询，直接更新的,需要Attach和State
///
/// 如果是已经在context，只能再封装一个(在具体的service)
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="t"></param>
public void Update<T>(T t) where T : class
{
if (t == null) throw new Exception("t is null");

this.Context.Set<T>().Attach(t);//将数据附加到上下文，支持实体修改和新实体，重置为UnChanged
this.Context.Entry<T>(t).State = EntityState.Modified;
this.Commit();//保存 然后重置为UnChanged
}

public void Update<T>(IEnumerable<T> tList) where T : class
{
foreach (var t in tList)
{
this.Context.Set<T>().Attach(t);
this.Context.Entry<T>(t).State = EntityState.Modified;
}
this.Commit();
}

#endregion

#region Delete
/// <summary>
/// 先附加 再删除
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="t"></param>
public void Delete<T>(T t) where T : class
{
if (t == null) throw new Exception("t is null");
this.Context.Set<T>().Attach(t);
this.Context.Set<T>().Remove(t);
this.Commit();
}

/// <summary>
/// 还可以增加非即时commit版本的，
/// 做成protected
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="Id"></param>
public void Delete<T>(int Id) where T : class
{
T t = this.Find<T>(Id);//也可以附加
if (t == null) throw new Exception("t is null");
this.Context.Set<T>().Remove(t);
this.Commit();
}

public void Delete<T>(IEnumerable<T> tList) where T : class
{
foreach (var t in tList)
{
this.Context.Set<T>().Attach(t);
}
this.Context.Set<T>().RemoveRange(tList);
this.Commit();
}
#endregion

#region Other
public void Commit()
{
this.Context.SaveChanges();
}

public IQueryable<T> ExcuteQuery<T>(string sql, SqlParameter[] parameters) where T : class
{
return this.Context.Database.SqlQuery<T>(sql, parameters).AsQueryable();
}

public void Excute<T>(string sql, SqlParameter[] parameters) where T : class
{
DbContextTransaction trans = null;
try
{
trans = this.Context.Database.BeginTransaction();
this.Context.Database.ExecuteSqlCommand(sql, parameters);
trans.Commit();
}
catch (Exception ex)
{
if (trans != null)
trans.Rollback();
throw ex;
}
}

public virtual void Dispose()
{
if (this.Context != null)
{
this.Context.Dispose();
}
}
#endregion

public class PageResult<T>
{
public int TotalCount { get; set; }
public int PageIndex { get; set; }
public int PageSize { get; set; }
public List<T> DataList { get; set; }
}
}