EntityFramework.dll中发生类型为'System.Data.Entity.ModelConfiguration.ModelValidationException'的异常 [英] An exception of type 'System.Data.Entity.ModelConfiguration.ModelValidationException' occurred in EntityFramework.dll

问题描述

错误-EntityFramework.dll中发生类型为'System.Data.Entity.ModelConfiguration.ModelValidationException'的异常，但未在用户代码中处理 附加信息:在模型生成过程中检测到一个或多个验证错误: MVCApplication.Models.Employee::EntityType'Employee'未定义键.定义此EntityType的键. 员工:EntityType:EntitySet员工"基于未定义键的员工"类型.

Error-An exception of type 'System.Data.Entity.ModelConfiguration.ModelValidationException' occurred in EntityFramework.dll but was not handled in user code Additional information: One or more validation errors were detected during model generation: MVCApplication.Models.Employee: : EntityType 'Employee' has no key defined. Define the key for this EntityType. Employees: EntityType: EntitySet 'Employees' is based on type 'Employee' that has no keys defined.

控制器代码:

namespace MVCApplication.Controllers
{
    public class EmployeeController : Controller
    {
        // GET: Employee
        public ActionResult Detail(int id)
        {
            EmployeeContext employeecontext = new EmployeeContext();
            Employee emp = employeecontext.Employees.Single(x => x.Emp_Id ==id);//here its throwing an exception
            return View("employee",emp);
        }
    }

这是我的模范员工班级:

this is my model employee class:

namespace MVCApplication.Models
{
    [Table("Employee")]
    public class Employee
    {
        public int Emp_Id { get; set; }
        public string Emp_Name { get; set; }
        public string Designation { get; set; }
        public string City { get; set; }
        public string State { get; set; }
        public string Country { get; set; }
    }
}

这是我的员工上下文类:

this is my employee context class:

namespace MVCApplication.Models
{
    public class EmployeeContext : DbContext
    {
        public DbSet<Employee> Employees { get; set; }
    }
}

推荐答案

您必须像这样将属性[Key]设置到模型中

You have to set attribute [Key] to your model, like this

[Table("Employee")]
public class Employee
{
    [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    [Key]
    public int Emp_Id { get; set; }
    public string Emp_Name { get; set; }
    public string Designation { get; set; }
    public string City { get; set; }
    public string State { get; set; }
    public string Country { get; set; }
}

仅当数据库生成ID时才使用[DatabaseGenerated(DatabaseGeneratedOption.Identity)]，否则不只是[Key]属性.

Use [DatabaseGenerated(DatabaseGeneratedOption.Identity)] only if your database generate ids, if not you just [Key] attribute.

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