我正在使用AutoMapper在两个集合之间进行映射。我看到的是，选项Ignore无法按预期在此方案中运行。我期待的可以在方法AutoMapperIgnore_TwoObjectMappedWithIgnoreId_SameWithUnchangedIdAndNewPrice()中看到。在其他两个测试方法中，Id虽然被忽略，但是集合中的每个对象都会再次创建，原因是原始值将会丢失。有可能使用UseDestinationValue，但我认为这只对集合所属的类有意义。如何在集合中使用选项Ignore？
[TestClass]
public class AutoMapperTests
{
private readonly IEnumerable<Dto> _testDtos;
private readonly IEnumerable<Entity> _testEntities;
public AutoMapperTests()
{
_testDtos = new List<Dto>
{
new Dto()
{
Id = 0,
Fk_Id = 8,
Price = 350000
}
};
_testEntities = new List<Entity>
{
new Entity()
{
Id = 8,
Price = 68000
}
,
new Entity()
{
Id = 6,
Price = 350000
}
};
}
[TestInitialize]
public void TestInitialize()
{
Mapper.Reset();
}
[TestMethod]
public void AutoMapperIgnore_TwoCollectionsWithOneCommonElementMappedFromDtoToEntityIgnoreId_SameWithUnchangedIdAndNewPrice()
{
//Assign
Mapper.CreateMap<Dto, Entity>()
.ForMember(destination => destination.Id, opt => opt.Ignore());
AutoMapperIgnore_TwoCollectionsWithOneCommonElementMappedFromDtoToEntity_SameWithUnchangedIdAndNewPrice(true);
}
[TestMethod]
public void AutoMapperIgnore_TwoCollectionsWithOneCommonElementMappedFromDtoToEntityUseDestinationtValueForId_SameWithUnchangedIdAndNewPrice()
{
//Assign
Mapper.CreateMap<Dto, Entity>()
.ForMember(destination => destination.Id, opt => opt.UseDestinationValue());
AutoMapperIgnore_TwoCollectionsWithOneCommonElementMappedFromDtoToEntity_SameWithUnchangedIdAndNewPrice(true);
}
private void AutoMapperIgnore_TwoCollectionsWithOneCommonElementMappedFromDtoToEntity_SameWithUnchangedIdAndNewPrice(bool isExceptedSame)
{
//Assign
var exceptedPrice = _testDtos.First().Price;
//Act
IEnumerable<Entity> foundEntities = _testEntities.Join(_testDtos, e => e.Id, e => e.Fk_Id, (entity, dto) => entity).ToList();
Entity entityBeforeMapping = foundEntities.First();
Mapper.Map(_testDtos, foundEntities);
Entity entityAfterMapping = foundEntities.First();
//Assert
if (isExceptedSame)
{
Assert.AreSame(entityBeforeMapping, entityAfterMapping);
}
Assert.AreEqual(entityBeforeMapping.Id, entityAfterMapping.Id);
Assert.AreEqual(exceptedPrice, entityAfterMapping.Price);
}
[TestMethod]
public void AutoMapperIgnore_TwoObjectMappedWithIgnoreId_SameWithUnchangedIdAndNewPrice()
{
//Assign
Mapper.CreateMap<Dto, Entity>()
.ForMember(destination => destination.Id, opt => opt.Ignore());
var testDto = new Dto()
{
Id = 0,
Fk_Id = 8,
Price = 350000
};
var testEntity = new Entity()
{
Id = 8,
Price = 68000
};
var exceptedPrice = testDto.Price;
//Act
Entity entityBeforeMapping = testEntity;
Mapper.Map(testDto, testEntity);
Entity entityAfterMapping = testEntity;
//Assert
Assert.AreSame(entityBeforeMapping, entityAfterMapping);
Assert.AreEqual(entityBeforeMapping.Id, entityAfterMapping.Id);
Assert.AreEqual(exceptedPrice, entityAfterMapping.Price);
}
internal class Dto
{
public int Id { get; set; }
public int Fk_Id { get; set; }
public Single? Price { get; set; }
}
internal class Entity
{
public int Id { get; set; }
public Single? Price { get; set; }
}
}
答案 0 :(得分：1)
正如@Stef所提到的，你必须单独映射集合中的每个条目，比如
_testEntities.Join(_testDtos, e => e.Id, e => e.Fk_Id, (entity, dto) => Mapper.Map(dto,entity));
这里是完整的功能示例：
[TestClass]
public class AutoMapperTests
{
private readonly IEnumerable<Dto> _testDtos;
private readonly IEnumerable<Entity> _testEntities;
public AutoMapperTests()
{
_testDtos = new List<Dto>
{
new Dto()
{
Id = 0,
Fk_Id = 8,
Price = 350000
}
};
_testEntities = new List<Entity>
{
new Entity()
{
Id = 8,
Price = 68000
}
,
new Entity()
{
Id = 6,
Price = 350000
}
};
}
[TestInitialize]
public void TestInitialize()
{
Mapper.Reset();
}
[TestMethod]
public void AutoMapperIgnore_TwoCollectionsWithOneCommonElementMappedFromDtoToEntityIgnoreId_SameWithUnchangedIdAndNewPrice()
{
//Assign
Mapper.CreateMap<Dto, Entity>()
.ForMember(destination => destination.Id, opt => opt.Ignore());
AutoMapperIgnore_TwoCollectionsWithOneCommonElementMappedFromDtoToEntity_SameWithUnchangedIdAndNewPrice(true);
}
[TestMethod]
public void AutoMapperIgnore_TwoCollectionsWithOneCommonElementMappedFromDtoToEntityUseDestinationtValueForId_SameWithUnchangedIdAndNewPrice()
{
//Assign
Mapper.CreateMap<Dto, Entity>()
.ForMember(destination => destination.Id, opt => opt.UseDestinationValue());
AutoMapperIgnore_TwoCollectionsWithOneCommonElementMappedFromDtoToEntity_SameWithUnchangedIdAndNewPrice(true);
}
private void AutoMapperIgnore_TwoCollectionsWithOneCommonElementMappedFromDtoToEntity_SameWithUnchangedIdAndNewPrice(bool isExceptedSame)
{
//Assign
var exceptedPrice = _testDtos.First().Price;
//Act
Entity entityBeforeMapping = _testEntities.First(testEntity => testEntity.Id == _testEntities.First().Id);
IEnumerable<Entity> foundEntities = _testEntities.Join(_testDtos, e => e.Id, e => e.Fk_Id, (entity, dto) => Mapper.Map(dto,entity));
Entity entityAfterMapping = foundEntities.First();
//Assert
if (isExceptedSame)
{
Assert.AreSame(entityBeforeMapping, entityAfterMapping);
}
Assert.AreEqual(entityBeforeMapping.Id, entityAfterMapping.Id);
Assert.AreEqual(exceptedPrice, entityAfterMapping.Price);
}
[TestMethod]
public void AutoMapperIgnore_TwoObjectMappedWithIgnoreId_SameWithUnchangedIdAndNewPrice()
{
//Assign
Mapper.CreateMap<Dto, Entity>()
.ForMember(destination => destination.Id, opt => opt.Ignore());
var testDto = new Dto()
{
Id = 0,
Fk_Id = 8,
Price = 350000
};
var testEntity = new Entity()
{
Id = 8,
Price = 68000
};
var exceptedPrice = testDto.Price;
//Act
Entity entityBeforeMapping = testEntity;
Mapper.Map(testDto, testEntity);
Entity entityAfterMapping = testEntity;
//Assert
Assert.AreSame(entityBeforeMapping, entityAfterMapping);
Assert.AreEqual(entityBeforeMapping.Id, entityAfterMapping.Id);
Assert.AreEqual(exceptedPrice, entityAfterMapping.Price);
}
internal class Dto
{
public int Id { get; set; }
public int Fk_Id { get; set; }
public Single? Price { get; set; }
}
internal class Entity
{
public int Id { get; set; }
public Single? Price { get; set; }
}
}
答案 1 :(得分：0)
我做了一些测试并确认了你的问题。
当映射IEnumerable列表时，AutoMapper会创建一个新的IEnumerable列表，该列表仅包含您定义要映射的属性，因此只有“Price”。
为了将Dto映射到实体，您需要定义一个使它们唯一的属性，如PrimaryKey。
class Dto
{
public long PrimaryKey { get; set; }
public int Id { get; set; }
public int Fk_Id { get; set; }
public Single? Price { get; set; }
}
class Entity
{
public long PrimaryKey { get; set; }
public int Id { get; set; }
public Single? Price { get; set; }
}
将列表映射到列表可以这样做：
// Update entities in original list
foreach (var d in _testDtos)
{
foreach (var e in _testEntities)
{
if (e.PrimaryKey == d.PrimaryKey)
{
Mapper.Map(d, e);
}
}
}
或者更友好的linq：
// Create a new list
var foundEntities = _testEntities.Join(_testDtos, e => e.PrimaryKey, d => d.PrimaryKey, (entity, dto) => Mapper.Map<Entity>(dto)).ToList();