Question

我正在尝试使用Visual Studio C＃中的列表项来使用Linq概念。我收到了错误：

非静态字段，对象，属性，方法
需要对象引用

用于书单。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Linq.List
{
    public class Books
    {
        string Title="title";
        string Author="author";
        string Publisher="publisher";
        int Year=2000;

        public  List <Books> booklist = new List<Books>
        {
            new  Books
            {
                Title="Programming C#",
                Author="Jesse Liberty",
                Publisher="O'reilly",
                Year=2008
            },
            new  Books
            {
                Title="Learning C#",
                Author="Jesse Liberty",
                Publisher="O'reilly",
                Year=2008
            },
            new  Books
            {
                Title="Programming php",
                Author="Kevin Ludorf",
                Publisher="O'reilly",
                Year=2008
            }
        };

        static void Main()
        {
            var ResultAuthor1= from b in booklist where b ResultAuthor1=="JesseLIberty"
            select new { b.Title,b.Author};

             foreach(var r in ResultAuthor1)
             {
                 Console.WriteLine(r.Title+" by "+r.Author);
             }
        }
    }
}       // please rectify this code if there is any error

Answer 1

您可以从SébastienSevrin将上面列出的静态列表标记为静态，也可以在Main中创建books - 类的实例：

Books books = new Books();
var ResultAuthor1= from b in books.booklist where b.Author == "JesseLIberty"

Answer 2

您的书单应该是静态的：

public static List <Books> booklist = new List<Books>
    {
        new  Books
        {
            Title="Programming C#",
            Author="Jesse Liberty",
            Publisher="O'reilly",
            Year=2008

        },

         new  Books
        {
            Title="Learning C#",
            Author="Jesse Liberty",
            Publisher="O'reilly",
            Year=2008

        },
         new  Books
        {
            Title="Programming php",
            Author="Kevin Ludorf",
            Publisher="O'reilly",
            Year=2008
        }
    };

修改
看起来你正在寻找文件：
Here是此错误的MSDN页面 Here是另一个MSDN页面，其中包含有关静态类的更多详细信息。

Answer 3

更改

  public  List <Books> booklist = new List<Books>

到

  public static List <Books> booklist = new List<Books>

如何调试“非静态字段需要对象引用”

3 个答案: