LINQ的All的方法

方法All返回布尔值bool，判断集合中是否所有元素都满足某一条件，通俗一点说，就是每一个元素，均符合同一个条件，它才返回真，不然返回假。

举列，创建一个model:

 

source code:

namespace Insus.NET.Models{   public class Book    {        public string Publishing { get; set; }        public string ISBN { get; set; }        public DateTime PublicationDate  { get; set; }    }}

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在ASP.NET MVC的视图片中，实现：

source code:

 Book[] books = { new Book { Publishing = "商务出版社",ISBN="13468564394",PublicationDate=Convert.ToDateTime("2016-04-13")},                             new Book { Publishing = "中华出版社",ISBN="56634565746",PublicationDate=Convert.ToDateTime("2016-01-19")},                             new Book { Publishing = "海天出版社",ISBN="78234235454",PublicationDate=Convert.ToDateTime("2016-03-22")},                             new Book { Publishing = "云贵出版社",ISBN="46724356756",PublicationDate=Convert.ToDateTime("2016-02-22")}            };            IEnumerable<Book> query = from bk in books                                      where books.All(b => b.PublicationDate > Convert.ToDateTime("2016-01-01"))                                      select bk;            query.ForEach(delegate (Book b)            {                WriteLiteral(string.Format("publishing: {0}; ISBN: {1}; Publication Date: {2} <br />",                                            b.Publishing,                                            b.ISBN,                                            b.PublicationDate.ToString("yyyy-MM-dd")));            });

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更好理解，修改一下：