AutoMapper为什么会引发错误AutoMapperConfigurationException？

Question

我有四个类-两个视图模型和两个实体：

PhoneNumberTypeViewModel：

public class PhoneNumberTypeViewModel
{
    public int Id { get; private set; }

    public string Description { get; set; }

    public PhoneNumberTypeViewModel(int id, string description)
    {
        Id = id;
        Description = description;
    }
}

PhoneNumberViewModel：

public class PhoneNumberViewModel
{
    public string PhNumber { get; set; }

    public PhoneNumberTypeViewModel PhoneType { get; set; }

    public PhoneNumberViewModel(string phNumber, PhoneNumberTypeViewModel phoneType)
    {
        PhNumber = phNumber;
        PhoneType = phoneType;
    }
}

PhoneNumberType：

public class PhoneNumberType : ValueObject
{
    public static readonly PhoneNumberType Home = new PhoneNumberType(1, "Home");

    public static readonly PhoneNumberType Office = new PhoneNumberType(2, "Office");

    public static readonly PhoneNumberType Cell = new PhoneNumberType(3, "Cell");

    public static readonly PhoneNumberType[] AllStatuses = { Home, Office, Cell };

    public int Id { get; }
    public string Description { get; private set;}

    private PhoneNumberType()
    {
    }

    public PhoneNumberType(int id, string description)
    {
        Id = id;
        Description = description;
    }
}

电话号码：

public class PhoneNumber : ValueObject
{
    public int Id { get;  private set; }

    [Phone]
    public string PhNumber { get; private set;}

    public PhoneNumberType PhoneType { get; }

    private PhoneNumber()
    {
    }

    public PhoneNumber(string phNumber, PhoneNumberType phoneType)
    {
        PhNumber = phNumber;
        PhoneType = phoneType;
    }
}

我使用AutoMapper映射类：

var config1 = new MapperConfiguration(cfg => cfg.CreateMap<PhoneNumberType, PhoneNumberTypeViewModel>().ReverseMap());
var config2 = new MapperConfiguration(cfg => cfg.CreateMap<PhoneNumber, PhoneNumberViewModel>());

然后我尝试使用以下方法验证配置：

            config1.AssertConfigurationIsValid();
            config2.AssertConfigurationIsValid();

对config2的验证将引发以下异常：

+       $exception  {"The following member on JobAssist.Services.ConnectionMgmt.API.Application.ViewModels.PhoneNumberViewModel cannot be mapped: \n\tPhoneType \nAdd a custom mapping expression, ignore, add a custom resolver, or modify the destination type JobAssist.Services.ConnectionMgmt.API.Application.ViewModels.PhoneNumberViewModel.\nContext:\n\tMapping to member PhoneType from JobAssist.Services.ConnectionMgmt.Domain.AggregatesModel.ConnectionManagerAggregate.PhoneNumber to JobAssist.Services.ConnectionMgmt.API.Application.ViewModels.PhoneNumberViewModel\nException of type 'AutoMapper.AutoMapperConfigurationException' was thrown."}   AutoMapper.AutoMapperConfigurationException

Config1通过验证，所以Config2为什么抛出此错误？

Answer 1

我发现了问题：在上面的代码中，我删除了对无效参数的检查。在PhoneNumberViewModel的构造函数中，我正在检查phoneType是否为null。我猜想Automapper在构造实体后会调用setter方法。