NHibernate学习(7)—对于实现机理的猜测

这两天看了老赵的三篇关于NHibernate的文章，很受启发。
首先，对于如下代码的思考，对于一个Model类的代理做到不覆盖父类属性的处理方法的方式

public class ArticleLazyProxy : Article
{
    public override string TagNames
    {
        get
        {
            var tagNames =  // 加载数据
            base.TagNames = tagNames;
            return base.TagNames;
        }
        set
        {
            base.TagNames = value;
        }
    }
}

其次，对于NHibernate对于集合属性管理方面，确实做只读和只写两套
public partial class Question
{    
    private static PropertyChangingEventArgs emptyChangingEventArgs = new PropertyChangingEventArgs(String.Empty);
    
    private int _QuestionID;
    
    private string _Name;
    
    private EntitySet<Answer> _Answers;
    
    public Question()
    {
        this._Answers = new EntitySet<Answer>(
            new Action<Answer>(this.attach_Answers),
            new Action<Answer>(this.detach_Answers));
    }
    
    public int QuestionID {  }
    
    public string Name {  }
    
    public EntitySet<Answer> Answers
    {
        get
        {
            return this._Answers;
        }
        set
        {
            this._Answers.Assign(value);
        }
    }
    
    private void attach_Answers(Answer entity)
    {
        entity.Question = this;
    }
    
    private void detach_Answers(Answer entity)
    {
        entity.Question = null;
    }
}属性集合在提高代码效率上确实很有必要，文中提到的Linq to SQL的处理方式给出了很巧妙的解决方式，即利用EntitySet<T>(Action 添加集合属性处理方法,Action 移除集合属性处理方法)来做到关系的维护。代码如下：

public partial class Question
{    
    private static PropertyChangingEventArgs emptyChangingEventArgs = new PropertyChangingEventArgs(String.Empty);
    
    private int _QuestionID;
    
    private string _Name;
    
    private EntitySet<Answer> _Answers;
    
    public Question()
    {
        this._Answers = new EntitySet<Answer>(
            new Action<Answer>(this.attach_Answers),
            new Action<Answer>(this.detach_Answers));
    }
    
    public int QuestionID { ... }
    
    public string Name { ... }
    
    public EntitySet<Answer> Answers
    {
        get
        {
            return this._Answers;
        }
        set
        {
            this._Answers.Assign(value);
        }
    }
    
    private void attach_Answers(Answer entity)
    {
        entity.Question = this;
    }
    
    private void detach_Answers(Answer entity)
    {
        entity.Question = null;
    }
}

本文参考自：我对NHibernate的感受（3）：有些尴尬的集合支持

赵劼 / CC BY 2.5