实体“学生”需要定义主键

Posted 2023-02-20

[为Student控制器创建视图时遇到此问题，我正在使用SQL Server和Visual Studio 2019。

我正在使用这些依赖项

• Microsoft.CodeAnalysis.Razor版本= 2.1.1
• Microsoft.EntityFrameworkCore版本= 2.1.1“
• Microsoft.EntityFrameworkCore.SqlServer版本= 2.1.1
• Microsoft.EntityFrameworkCore.Tools版本= 2.1.1

=== Student.CS ===

using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.Linq;
using System.Threading.Tasks;

namespace ASP_Core_EF.Models

    public enum Status  UnderGraduate, PostGraduate, Masters, Phd, Suspended 

    public class Student
    
        [Key]
        public int StudentId  get; 

        public string FirstName  get; set; 
        public string LastName  get; set; 
        [DataType(DataType.Date)]
        public DateTime DOB  get; set; 
        [DataType(DataType.Date)]
        public DateTime RegistrationDate  get; set; 

        public int GenderId  get; set; 
        public Status? Status  get; set; 
    

=== DB_Context.CS ===

using ASP_Core_EF.Models;
using Microsoft.EntityFrameworkCore;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

namespace ASP_Core_EF.Repository

    public class DB_Context : DbContext
    
        public DB_Context(DbContextOptions<DB_Context> options ) : base(options)  

        public DbSet<Student> Students  get; set; 
        public DbSet<Course> Courses  get; set; 

        public DbSet<Gender> Gender  get; set; 

        public DbSet<Enrollment> Enrollments  get; set; 
   

答案

您缺少集合属性，因此出现错误

[Key]
public int StudentId  get; set;

或

[Key]
public int StudentId  get; private set;