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System.Data.SqlClient客户端.SqlException:列名“Gender\u id”无效

entity-framework asp.net-mvc asp.net c#

Danial Ahmed · 技术社区 · 6 年前

我正在学习Web应用程序开发asp.netmvc和实体框架。我有一个数据库,有3个表,分别是学生、性别和课程。我遇到了这个问题。

错误在第23行。

列名“Genders\u Id”无效。

异常详细信息: 列名“Programs\u Id”无效。

Source Error:


Line 21:         {
Line 22:             StudentsContext stdContext = new StudentsContext();
Line 23:             Students students = stdContext.Students.Single(std => std.Id == id);
Line 24:             //ViewBag.Student = students;
Line 25:             return View(students);

namespace WebApplication4.Models
{
  public class Students
  {
     public string Name { get; set; }
     public int Id { get; set; }
     public int Gender { get; set; }
     public int Program { get; set; }
     public string Country { get; set; }
   }
}

public class StudentsContext:DbContext
{
    public DbSet<Students> Students { get; set; }
    public DbSet<Programs> Programs { get; set; }
    public DbSet<Genders> Genders { get; set; }
}

public class Programs
{
    public int Id { get; set; }
    public string Program { get; set; }
    public List<Students> Students { get; set; }
}

public class Genders
{
    public int Id { get; set; }
    public string Gender { get; set; }
    public List<Students> Students { get; set; }
}

数据库表:

2 回复 | 直到 6 年前

Ivan Stoev 6 年前

Genders_Id 和 Programs_Id Genders.Students 和 Programs.Students 集合导航属性。

[ForeinKey] 数据注释:

public class Programs
{
    // ...
    [ForeignKey("Program")]
    public List<Students> Students { get; set; }
}

public class Genders
{
    // ...
    [ForeignKey("Gender")]
    public List<Students> Students { get; set; }
}

或者(我的首选)fluent API:

protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
    // ...

    modelBuilder.Entity<Genders>()
        .HasMany(e => e.Students)
        .WithRequired()
        .HasForeignKey(e => e.Gender);

    modelBuilder.Entity<Programs>()
        .HasMany(e => e.Students)
        .WithRequired()
        .HasForeignKey(e => e.Program);
}