Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
725 views
in Technique[技术] by (71.8m points)

c# - Overriding List<T>'s Add()

Can't i overload List's Add method ?

class ListDemo<T>:List<T>
 {
    public override T  Add<T>(T value)
   {
      return base.Add(value);
   }
}

I am receiving the following error :

1) Type parameter 'T' has the same name as the type parameter from outer type 'CollectionsExample.ListDemo

2) 'CollectionsExample.ListDemo.Add(T)': no suitable method found to override

See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Reply

0 votes
by (71.8m points)

Instead of subclassing from List<T>, you should encapsulate List<T> and implement IList<T>. This makes it easy to handle "overriding" the behavior of Add:

public class ListDemo<T> : IList<T>
{
    private List<T> list = new List<T>(); // Internal list
    public void Add(T item)
    {
       // Do your pre-add logic here
       list.Add(item); // add to the internal list
       // Do your post-add logic here
    }

    // Implement all IList<T> methods, just passing through to list, such as:
}

List<T> should not be part of your public API - it should be an implementation detail.


与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
OGeek|极客中国-欢迎来到极客的世界,一个免费开放的程序员编程交流平台!开放,进步,分享!让技术改变生活,让极客改变未来! Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...