将HasMany和ManyToMany关系公开为IEnumerable [英] Exposing HasMany and ManyToMany relationships as IEnumerable

问题描述

目前在我的实体中，我将我的集合作为IList公开，但我一直在考虑将它们公开为IEnumerable，以防止用户手动添加到集合中。我对这些操作有具体的补充，以便我可以确保我的双向关系保持不变。在这种情况下，有几个问题想起来。

1. 如果我将它们暴露为IEnumberable，这是否意味着我需要一个Add和Remove方法来表示每个集合中的一个关系？


2. 有没有更简单的方法来做到这一点？我不反对这样做只是想知道。


3. 您是这样做的吗？
   
   

     public class OrderHeader 
    {
    public virtual Guid OrderId {get;私人设置} 
    
   公共虚拟IList< OrderLine> OrderLines {get;组; } 
    
    public virtual void AddLine（OrderLine orderLine）
    {
    orderLine.Order = this; 
    OrderLines.Add（orderLine）; 
   } 
    
    //因为我们将集合公开为IList 
   } 
     

   
   
   转换上面的类以便我们只暴露IEnumerable会导致：
   
   pre $ code public class OrderHeader
   {
   public virtual Guid OrderId {get;私人设置}
   
   私有IList< OrderLine> orderLines {get;组; }
   public IEnumerable< OrderLine> OrderLines {get {return orderLines; }}
   
   public virtual void AddLine（OrderLine orderLine）
   {
   orderLine.Order = this;
   orderLines.Add（orderLine）;
   
   $ b $ public virtual void RemoveLine（OrderLine orderLine）
   {
   orderLines.Remove（orderLine）;
   
   
   $ / code $ / pre
   

   解决方案

   
   
   1. 是的，如果你公开一个IEnumerable，最好在这个类上添加方法来处理Add / Remove
   
   
   2. 私有后台是一个很好的解决方案。 li>
      
   3. 是的，但请记住，如果你想真正只读访问暴露的集合使用ReadOnlyCollection - http://msdn.microsoft.com/zh-CN/library/ms132474.aspx
   
   

   
   

   Currently in my entities I'm exposing my collections as an IList but I've been thinking about exposing them as a IEnumerable to prevent users from manually adding to the collections. I have specific adds for these operations so that I can make sure my bi-directional relationships stay intact. A couple questions come to mind in this scenario.

   1. If I expose them as IEnumberable does this mean I'll need an Add and Remove method for every collection that represents a relationship in my entities?
   2. Is there an easier way to do this? I'm not against doing it this way just wondering.
   3. Are you doing it this way?

   Example:

   public class OrderHeader
   {
       public virtual Guid OrderId { get; private set; }
   
       public virtual IList<OrderLine> OrderLines { get; set; }
   
       public virtual void AddLine(OrderLine orderLine)
       {
           orderLine.Order = this;
           OrderLines.Add(orderLine);
       }
   
       //No need for a remove method since we expose collection as IList
   }
   

   Converting the class above so that we only expose IEnumerable would result in:

   public class OrderHeader
   {
       public virtual Guid OrderId { get; private set; }
   
       private IList<OrderLine> orderLines { get; set; }
       public IEnumerable<OrderLine> OrderLines { get { return orderLines; } }
   
       public virtual void AddLine(OrderLine orderLine)
       {
           orderLine.Order = this;
           orderLines.Add(orderLine);
       }
   
       public virtual void RemoveLine(OrderLine orderLine)
       {
           orderLines.Remove(orderLine);
       }
   }
   

   解决方案

   1. Yes, if you expose an IEnumerable it is best to add methods on the class to handle Add/Remove
   2. A private backing field is a pretty good solution.
   3. Yes, but keep in mind if you want truly read only access to the exposed collection use ReadOnlyCollection - http://msdn.microsoft.com/en-us/library/ms132474.aspx

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