LINQ基础之联合查询

最新推荐文章于 2024-07-15 19:26:06 发布

原创最新推荐文章于 2024-07-15 19:26:06 发布 · 769 阅读

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文章标签：

#linq #出版 #string #books #delphi #asp.net

ADO.NET数据访问同时被 2 个专栏收录

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1、创建两个类：Book和PublishInfo；

//书籍类
    public class Book
    {
        public Book()
        {
        }

        public string BookName { get; set; }
        public string ISBN { get; set; }
        public double Price { get; set; }
        public string Publish { get; set; }
    }
    //出版社类
    public class PublishInfo
    {
        public PublishInfo()
        {
        }
        public string PublishName { get; set; }
        public string Address { get; set; }
        public string Contact { get; set; }
        public string Phone { get; set; }

}

2、添加一个按钮事件，处理代码如下：
protected void btnJoinOperation_Click(object sender, EventArgs e)
{

//我直接了填充数据，以查看处理结果
        List<Book> books = new List<Book>()
        {
            new Book(){BookName="C#程序设计", ISBN="123456", Price= 34.5, Publish="A出版社"},
            new Book(){BookName="ASP.NET", ISBN="123456", Price= 34.5, Publish="B出版社"},
            new Book(){BookName="C++", ISBN="123456", Price= 34.5, Publish="A出版社"},
            new Book(){BookName="Java", ISBN="123456", Price= 34.5, Publish="D出版社"},
            new Book(){BookName="Delphi", ISBN="123456", Price= 34.5, Publish="F出版社"},
            new Book(){BookName=".NET程序设计", ISBN="123456", Price= 34.5, Publish="F出版社"},
        };
        List<PublishInfo> publishes = new List<PublishInfo>()
        {
            new PublishInfo(){PublishName="A出版社", Address="地址1", Contact="孙悟空", Phone="3343568"},
            new PublishInfo(){PublishName="B出版社", Address="地址2", Contact="孙悟空2", Phone="3343568"},
            new PublishInfo(){PublishName="C出版社", Address="地址3", Contact="孙悟空3", Phone="3343568"},
            new PublishInfo(){PublishName="D出版社", Address="地址4", Contact="孙悟空4", Phone="3343568"},
            new PublishInfo(){PublishName="E出版社", Address="地址5", Contact="孙悟空5", Phone="3343568"},
            new PublishInfo(){PublishName="F出版社", Address="地址6", Contact="孙悟空6", Phone="3343568"},
        };

        //使用连接查询，并取出书籍与出版社信息
        var BookandPublish = from book in books
                             join publish in publishes
                             on book.Publish equals publish.PublishName
                             select new
                             {
                                 书籍名称 = book.BookName,
                                 出版社名称 = book.Publish,
                                 出版社地址 = publish.Address,
                                 出版社联系人= publish.Contact,
                                 出版社电话 = publish.Phone
                             };
        //绑定到控件GridView
        GridView1.DataSource = BookandPublish;
        GridView1.DataBind();
    }

3、输出结果：