C# dbContext.SaveChanges（）不保存也不输出错误

我试图在我的MVC项目中更新一个用户对象，但它似乎没有保存我输入的新值

有人能看出我做错了什么吗

这就是我进行保存的方法，我知道我可以一直保存到

db.SaveChanges（）Debug.WriteLines（）

捕获异常的输出：

System.Data.Entity.Validation.DbEntityValidationException: Validation failed for one or more entities. See 'EntityValidationErrors' property for more details.
at System.Data.Entity.Internal.InternalContext.SaveChanges()
at System.Data.Entity.Internal.LazyInternalContext.SaveChanges()
at System.Data.Entity.DbContext.SaveChanges()
at Oblig1.DBUser.editUser(String email, User innUser) in c:\Users\XXX\XXX\XXX\XXX\DBUser.cs:line 55

错误的输出：

A first chance exception of type 'System.Data.Entity.Validation.DbEntityValidationException' occurred in EntityFramework.dll
Entity of type "City" in state "Added" has the following validation errors:
- Property: "Postcode", Error: "Postcode must be added"
Entity of type "User_546F9926F8DC53E2EF66BA48BE431DF1B26DEBEFA54B0597E60AEB1839DD022C" in state "Modified" has the following validation errors:
- Property: "city", Error: "The city field is required."

我使用的模型有三个表：

public class User
{
    [Required(ErrorMessage = "Firstname must be added")]
    public string Firstname { get; set; }

    [Required(ErrorMessage = "Surname must be added")]
    public string Surname { get; set; }

    [Required(ErrorMessage = "Address must be added")]
    public string Address { get; set; }

    public string Postcode { get; set; }

    [Key]
    [Required(ErrorMessage = "E-mail must be added")]
    [DataType(DataType.EmailAddress)]
    [EmailAddress]
    public string Email { get; set; }

    [Required(ErrorMessage = "Phonenr must be added")]
    public string Phonenr { get; set; }

    [Required(ErrorMessage = "Password must be added")]
    public string Password { get; set; }

    [Required]
    public virtual City city { get; set; }

    public virtual List<Order> Orders { get; set; }
}

public class dbUser
{
    [Key]
    public string Email { get; set; }
    public byte[] Password { get; set; }
}

public class City
{
    [Key]
    [Required(ErrorMessage = "Postcode must be added")]
    public string Postcode { get; set; }

    [Required(ErrorMessage = "City must be added")]
    public string Cityname { get; set; }
}

公共类用户
{
[必需（ErrorMessage=“必须添加Firstname”）]
公共字符串名{get；set；}
[必需（ErrorMessage=“必须添加姓氏”）]
公共字符串姓氏{get；set；}
[必需（ErrorMessage=“必须添加地址”）]
公共字符串地址{get；set；}
公共字符串邮政编码{get；set；}
[关键]
[必需（ErrorMessage=“必须添加电子邮件”）]
[数据类型（数据类型.电子邮件地址）]
[电邮地址]
公共字符串电子邮件{get；set；}
[必需（ErrorMessage=“必须添加Phonenr”）]
公共字符串Phonenr{get；set；}
[必需（ErrorMessage=“必须添加密码”）]
公共字符串密码{get；set；}
[必需]
公共虚拟城市城市{get；set；}
公共虚拟列表顺序{get；set；}
}
公共类dbUser
{
[关键]
公共字符串电子邮件{get；set；}
公共字节[]密码{get；set；}
}
公营城市
{
[关键]
[必需（ErrorMessage=“必须添加邮政编码”）]
公共字符串邮政编码{get；set；}
[必需（ErrorMessage=“必须添加城市”）]
公共字符串Cityname{get；set；}
}

创建新城市对象时，请执行以下操作：

var newCity = new City()
{
    Postcode = innUser.Postcode,
    Cityname = innUser.city.Cityname
};

相反，您需要使用

City.postcode

属性设置邮政编码，如下所示：

var newCity = new City()
{
    Postcode = innUser.city.Postcode,
    Cityname = innUser.city.Cityname
};

---

调试输出是什么样子的？当然！给我一点时间。看起来你得到了一个DbEntityValidationException。捕获异常，它将告诉您需要知道的内容（EntityValidationErrors属性）。您确定连接已打开吗@adamNature不够，您需要阅读

EntityValidationErrors

集合。

var newCity = new City()
{
    Postcode = innUser.city.Postcode,
    Cityname = innUser.city.Cityname
};