约束

where T:struct 使用结构约束,类型T必须是值类型

where T: class 类约束指定,类型T必须是引用类型

where T: IFoo 必须执行接口IFoo

where T:Foo 必须派生于基类Foo

where T:new() 必须有一个默认构造函数

where T:U  约束可以指定,类型T1 派生于泛型类型T2。也称为裸类型约束

多个约束可以合并 where T:IFoo,new()

继承

静态成员

泛型接口

泛型方法

泛型委托

 

 //泛型接口
    //public sealed delegate void EventHandler<TeventArgs>(object sender,TeventArgs e) where TeventArgs:EventArgs;

    public class DocumentManager<T> where T:IDocument //必须继承IDocument接口
    {
        private readonly Queue<T> documentQueue = new Queue<T>();
        public void AddDocument(T doc)
        {
            lock (this)
            {
                documentQueue.Enqueue(doc);
            }
        }
        public bool IsDocumentAvailable
        {
            get { return documentQueue.Count > 0; }
        }
        public T GetDocument()
        {
            T doc = default(T);  //default null 或 0
            lock (this)
            {
                doc = documentQueue.Dequeue();
            }
            return doc;
        }

        public void DisplayAllDocuments()
        {
            foreach (T doc in documentQueue)
            {
                Console.WriteLine(doc.title);
            }
        }
    }
    //public static


    public interface IDocument
    {
        string title { get; set; }
        string content { get; set; }
    }
    public class Document : IDocument
    {
        public string title { get; set; }
        public string content { get; set; }
        public Document()
        { }
        public Document(string title, string content)
        {
            this.title = title;
            this.content = content;
        }
    }

    // 泛型类需要调用泛型上的方法,就必须添加约束
    class Program
    {

static void Main(string[] args)
        {
            DocumentManager<Document> dm = new DocumentManager<Document>();
            dm.AddDocument(new Document("Title A", "Sample A"));
            dm.AddDocument(new Document("Title B", "Sample B"));
            dm.DisplayAllDocuments();
            if (dm.IsDocumentAvailable)
            {
                Document d = dm.GetDocument();
                Console.WriteLine(d.content);
            }

            //Node<int, string> node = new Node<int, string>();
            //node.add(2, "11");
           
        

        }

        public static void Copy<R>(List<R> source, List<R> destination)
         {
             foreach (R obj in source)
          {
           destination.Add(obj);
          }
        }
    }