1

当我尝试在我的应用程序中调用 Mapper.Map 时出现以下异常：

AutoMapper.AutoMapperMappingException. 

Mapping types:
Double -> Double
System.Double -> System.Double

Destination path:
Address.Latitude

Source value:
42.250287

   System.InvalidCastException. Unable to cast object of type 'Acme.Order' to type 'Acme.Address'.

除了明显的错误表明它无法映射相同类型的对象（以及原始类型），事实是我从不从类型“Acme.Order”映射到类型“Acme.Address”！

这是正在使用的实际调用：

var order = Mapper.Map<IDataRecord, Order>(theDataReader);

我的对象模型如下所示：

public class Order
{
    public Address Address { get; set; }
    public Int32 Number { get; set; }
    public PhoneNumber PhoneNumber { get; set; }
}

public class Address
{
    public String City { get; set; }
    public Double Latitude { get; set; }
    public Double Longitude { get; set; }
    public Int32 Number { get; set; }
    public String PostalCode { get; set; }
    public String State { get; set; }
    public String Street { get; set; }
}

public class PhoneNumber
{
    public String Extension { get; set; }
    public String Number { get; set; }
}

我在我的应用程序中定义了以下配置：

CreateMap<IDataRecord, Address>()
.ForMember(target => target.Latitude, opt => opt.MapFrom(record => GetDoubleFrom(record, "Latitude", 0)))
.ForMember(target => target.Longitude, opt => opt.MapFrom(record => GetDoubleFrom(record, "Longitude", 0)))
;
CreateMap<IDataRecord, PhoneNumber>()
.ForMember(target => target.Extension, opt => opt.MapFrom(record => GetStringFrom(record, "Extension", String.Empty)))
.ForMember(target => target.Number, opt => opt.MapFrom(record => GetStringFrom(record, "PhoneNumber", String.Empty)))
;
CreateMap<IDataRecord, Order>()
.ForMember(target => target.Address, opt => opt.ResolveUsing(record => Mapper.Map<IDataRecord, Address>(record)))
.ForMember(target => target.PhoneNumber, opt => opt.ResolveUsing(record => Mapper.Map<IDataRecord, PhoneNumber>(record)))
;

使用这些辅助方法：

private Double GetDoubleFrom(IDataRecord record, String name, Double defaultValue)
{
    return (record.Contains(name) && !record.IsDbNull(name)) ? record.GetDouble(name) : defaultValue;
}

private String GetStringFrom(IDataRecord record, String name, String defaultValue)
{
    return (record.Contains(name) && !record.IsDbNull(name)) ? record.GetString(name) : defaultValue;
}

（我在 IDataRecord 上有扩展方法，它们采用字段名称、获取序数并使用标准方法返回值，但为简洁起见不会显示它们。）

这是否能说明导致失败的原因？

（顺便说一句，我正在使用 AutoMapper v2.1.267）

4

1 回答 1

1

我无法直接重新创建它，因为它缺少一些信息（例如IDataRecord接口的具体类、 的内容theDataReader等）。然而，第一个检查是确保您的映射是正确的。你用 测试它AssertConfigurationIsValid吗？

例如，如果您有以下 AutoMapper 配置文件：

public class MyProfile : Profile
{
    public override string ProfileName
    {
        get
        {
            return "MyProfile";
        }
    }

    protected override void Configure()
    {
        CreateMap<IDataRecord, Address>()
            .ForMember(
                target => target.Latitude,
                opt => opt.MapFrom(
                    record => GetDoubleFrom(record, "Latitude", 0)))
            .ForMember(
                target => target.Longitude,
                opt => opt.MapFrom(
                    record => GetDoubleFrom(record, "Longitude", 0)));
        CreateMap<IDataRecord, PhoneNumber>()
            .ForMember(
                target => target.Extension,
                opt => opt.MapFrom(
                    record => GetStringFrom(record, "Extension", string.Empty)))
            .ForMember(
                target => target.Number,
                opt => opt.MapFrom(
                    record => GetStringFrom(record, "PhoneNumber", string.Empty)));
        CreateMap<IDataRecord, Order>()
            .ForMember(
                target => target.Address,
                opt => opt.ResolveUsing(
                    record => Mapper.Map<IDataRecord, Address>(record)))
            .ForMember(
                target => target.PhoneNumber,
                opt => opt.ResolveUsing(
                    record => Mapper.Map<IDataRecord, PhoneNumber>(record)));
    }
}

这个单元测试会通过吗？

[Test]
public void AutoMapper_Configuration_IsValid()
{
    Mapper.Initialize(m => m.AddProfile<MyProfile>());
    Mapper.AssertConfigurationIsValid();
}

更新

你能试一下吗

CreateMap<IDataRecord, Order>()
    .ForMember(
        target => target.Address,
        opt => opt.MapFrom(record => Mapper.Map<IDataRecord, Address>(record)))
    .ForMember(
        target => target.PhoneNumber,
        opt => opt.MapFrom(record => Mapper.Map<IDataRecord, PhoneNumber>(record)));
于 2012-11-28T23:34:42.330 回答