EF的泛型封装 写的很好 转自Fly_Elephant http://www.cnblogs.com/xiaofeixiang/p/4188600.html?utm_source=tuic...

Entity Framework本身的增删改查其实 已经很方便了，不过做项目的时候用的多了也就觉得有点累了，每个业务实体基本上都涉及到到了增删改查这四个基本的要素，至于封装每个公司可能都不一样，接口，设计模式都用的眼花缭乱，我闲来没事就搞个简单的封装Helper，Github上也有关于EF的扩展Libray，具体没有用过，公司的有自己的封装，自己也没怎么弄，具体地址:https://github.com/loresoft/EntityFramework.Extended.

首先来看段代码，model和context是从数据中直接生成，你可以选择自己习惯的方式:

//新增
  User addUser = new User();
  addUser.PersonID = 3;
  addUser.UserName = "keso";
  dbContext.Entry<User>(addUser).State = EntityState.Added;  dbContext.SaveChanges();  //修改  User updateUser = new User();  dbContext.Users.Where(item => item.ID == 2).OrderBy(item => item.ID);  updateUser.UserName = updateUser.UserName + "测试";  dbContext.Entry<User>(updateUser).State = EntityState.Modified;  dbContext.SaveChanges();  //删除  User delUser = dbContext.Users.Where(item => item.ID == 2).First();  dbContext.Entry<User>(delUser).State = EntityState.Deleted;  dbContext.SaveChanges(); 

如果每个业务实体都这么写一遍，估计公司水准有待提高，而且开发的也该跳起来骂人，本人只是简单封装下新建一个EFHelper，实际开发会封装的更多，不过底层处理是不变的

class EFHelpler<T> where T : class { //... }

新增

方法:

/// 

  /// 实体新增  /// 
  ///   public void add(params T[] paramList)  {  foreach (var model in paramList)  {   dbContext.Entry(model).State = EntityState.Added;  }  dbContext.SaveChanges();  } 

调用:

EFHelpler<User> helper = new EFHelpler<User>();
    BaseContext dbContext = new BaseContext();    //新增    List<User> listUser = new List<User>();    for (int i = 0; i < 2; i++)    {     User user = new User();     user.PersonID = i;     user.UserName = "FlyElehant" + i;     listUser.Add(user);    }    helper.add(listUser.ToArray());    Console.WriteLine("新增成功"); 

查询

查询分了两种，一种是简单的查询，一种是分页的：

/// <summary>
    /// 实体查询
   /// summary>   public IEnumerable<T> getSearchList(System.Linq.Expressions.Expression<Funcbool>> where)   {    return dbContext.Set<T>().Where(where);   }   /// <summary>   /// 实体分页查询   /// summary>   /// <typeparam name="TKey">typeparam>   /// <param name="where">param>   /// <param name="orderBy">param>   /// <param name="pageSize">param>   /// <param name="pageIndex">param>   /// <returns>returns>   public IEnumerable<T> getSearchListByPage<TKey>(Expression<Funcbool>> where, Expression<FuncTKey>> orderBy, int pageSize, int pageIndex)   {    return dbContext.Set<T>().Where(where).OrderByDescending(orderBy).Skip((pageIndex - 1) * pageSize).Take(pageSize);   } 

简单调用，第二个方式除了分页之外，主要是查询的时候指定一定OrderBy的类型，也就是TKey:

var query = helper.getSearchList(item => item.UserName.Contains("keso"));
  var queryMulti = helper.getSearchListByPage(item => item.UserName.Contains("FlyElehant"), order => order.PersonID, 2, 1);  query = queryMulti;  foreach (User user in query)  {  Console.WriteLine(user.UserName);  } 

修改

修改代码稍微读了几行，主要是用到了一下反射:

/// <summary>
    /// 按照条件修改数据
   /// summary>   /// <param name="where">param>   /// <param name="dic">param>   public void update(Expression<Funcbool>> where, Dictionary<string, object> dic)   {    IEnumerable<T> result = dbContext.Set<T>().Where(where).ToList();    Type type = typeof(T);    List<PropertyInfo> propertyList = type.GetProperties(System.Reflection.BindingFlags.Public | System.Reflection.BindingFlags.Instance).ToList();    //遍历结果集    foreach (T entity in result)    {     foreach (PropertyInfo propertyInfo in propertyList)     {      string propertyName = propertyInfo.Name;      if (dic.ContainsKey(propertyName))      {       //设置值       propertyInfo.SetValue(entity, dic[propertyName], null);      }     }    }    dbContext.SaveChanges();   } 

调用:

Dictionary<string,object> dic=new Dictionary<string,object>();
            dic.Add("PersonID",2);
            dic.Add("UserName","keso");
            helper.update(item => item.UserName.Contains("keso"), dic);
            Console.WriteLine("修改成功");

删除

方法:

/// 

  /// 实体删除  /// 
  ///   public void delete(params T[] paramList)  {  foreach (var model in paramList)  {   dbContext.Entry(model).State = EntityState.Deleted;  }  dbContext.SaveChanges();  } 

调用:

var query = helper.getSearchList(item => item.UserName.Contains("keso"));
            helper.delete(query.ToArray());

完整的EFHelper:

class EFHelpler<T> where T : class
  {
    BaseContext dbContext = new BaseContext();
  /// <summary>   /// 实体新增   /// summary>   /// <param name="model">param>   public void add(params T[] paramList)   {    foreach (var model in paramList)    {     dbContext.Entry<T>(model).State = EntityState.Added;    }    dbContext.SaveChanges();   }   /// <summary>   /// 实体查询   /// summary>   public IEnumerable<T> getSearchList(System.Linq.Expressions.Expression<Funcbool>> where)   {    return dbContext.Set<T>().Where(where);   }   /// <summary>   /// 实体分页查询   /// summary>   /// <typeparam name="TKey">typeparam>   /// <param name="where">param>   /// <param name="orderBy">param>   /// <param name="pageSize">param>   /// <param name="pageIndex">param>   /// <returns>returns>   public IEnumerable<T> getSearchListByPage<TKey>(Expression<Funcbool>> where, Expression<FuncTKey>> orderBy, int pageSize, int pageIndex)   {    return dbContext.Set<T>().Where(where).OrderByDescending(orderBy).Skip((pageIndex - 1) * pageSize).Take(pageSize);   }   /// <summary>   /// 实体删除   /// summary>   /// <param name="model">param>   public void delete(params T[] paramList)   {    foreach (var model in paramList)    {     dbContext.Entry<T>(model).State = EntityState.Deleted;    }    dbContext.SaveChanges();   }   /// <summary>   /// 按照条件修改数据   /// summary>   /// <param name="where">param>   /// <param name="dic">param>   public void update(Expression<Funcbool>> where, Dictionary<string, object> dic)   {    IEnumerable<T> result = dbContext.Set<T>().Where(where).ToList();    Type type = typeof(T);    List<PropertyInfo> propertyList = type.GetProperties(System.Reflection.BindingFlags.Public | System.Reflection.BindingFlags.Instance).ToList();   

转载于:https://www.cnblogs.com/wangkaipeng/p/4506897.html