自动映射器未忽略嵌套属性

Question

我查看了各种类似的帖子，但无法发现我的错误。基本上，我有两个视图，更新“设置”对象的不同部分。视图模型包含两种属性中的一种，根据正在设置哪个属性，应忽略另一个属性。当ViewModel ==> Entity直接更新时，它运行良好，但是当Automapper尝试更新嵌套对象时，它会失败。

我有以下对象结构：

public class Account
{
    public int AccountId { get; set; }
    public DateTime DateToBeIgnored { get; set; }
    public AccountSetting Settings { get; set; }
}

public class AccountSetting
{
    public string PropertyOne { get; set; }
    public string PropertyTwo { get; set; }
}

public class AccountViewModel
{
    public int AccountId { get; set; }
    public DateTime DateToBeIgnored { get; set; }
    public AccountSettingViewModel Settings { get; set; }
}

public class AccountSettingViewModel
{
    public string PropertyTwo { get; set; }
}

public class OtherAccountSettingViewModel
{
    public string PropertyOne { get; set; }
}

使用以下映射：

void WireUpMappings()
{
    // From the entities to the view models
    Mapper.CreateMap<Account, AccountViewModel>();
    Mapper.CreateMap<AccountSetting, AccountSettingViewModel>();
    Mapper.CreateMap<AccountSetting, OtherAccountSettingViewModel>();

    // From the view models to the entities
    Mapper.CreateMap<AccountViewModel, Account>()
        .ForMember(dest => dest.DateToBeIgnored, opt => opt.Ignore());

    Mapper.CreateMap<AccountSettingViewModel, AccountSetting>()
        .ForMember(dest => dest.PropertyTwo, opt => opt.Ignore());

    Mapper.CreateMap<OtherAccountSettingViewModel, AccountSetting>()
        .ForMember(dest => dest.PropertyOne, opt => opt.Ignore());

    Mapper.AssertConfigurationIsValid();
}

当映射 [OtherAccountSettingViewModel --> AccountSetting] 时，只有 "PropertyTwo" 属性被分配了（而 "PropertyOne" 的原始值保持不变） - 这是我所期望的。

然而，当映射 [AccountViewModel --> Account] 时，“DateToBeIgnored”被正确忽略，而 Account.AccountSetting.PropertyTwo 的先前值被替换为“null”。

是否有人能发现我的错误？

- Tim

Answer 1

以下是解决方案：

[TestMethod]
public void TestMethod1()
{
     Mapper.CreateMap<AccountViewModel, Account>()
        .ForMember(dest => dest.DateToBeIgnored, opt => opt.Ignore())
        .ForMember(dest=>dest.Settings, opt=>opt.UseDestinationValue());

    Mapper.CreateMap<AccountSettingViewModel, AccountSetting>()
        .ForMember(dest=>dest.PropertyOne, opt=>opt.Ignore())
        .ForMember(dest => dest.PropertyTwo, opt => opt.MapFrom(a => a.PropertyTwo));

    Mapper.AssertConfigurationIsValid();

    AccountViewModel viewmodel = new AccountViewModel()
    {
        AccountId = 3,
        DateToBeIgnored = DateTime.Now,
        Settings = new AccountSettingViewModel() { PropertyTwo = "AccountSettingViewModelPropTwo" }
    };

    Account account = new Account()
    {
        AccountId = 10,
        DateToBeIgnored = DateTime.Now,
        Settings = new AccountSetting() { PropertyOne = "AccountPropOne", PropertyTwo = "AccountPropTwo" }
    };

    account = Mapper.Map<AccountViewModel, Account>(viewmodel, account);

    Assert.IsNotNull(account);

}

- Cybermaxs

---

Ah，使用UseDestinationValue，太好了，谢谢！我肯定尝试过，但我有一种感觉是我试图在属性上设置它。谢谢！ - Tim