Question

我有以下情况

实体框架类类：

public class Block
{
    public Guid Id { get; set; }
    public ICollection<BlockLocation> BlockLocations { get; set; }
    public BlockType Type { get; set; }
}

public class BlockLocation
{
    public Guid Id { get; set; }
    public Guid BlockId { get; set; }
    public Block Block { get; set; }
}

我的域实体看起来像

public class Block
{
    public Block(BlockType type = BlockType.None) : this()
    {
        Type = type;
    }

    private Block() { }

    public Guid Id { get; set; }
    public List<BlockLocation> BlockLocations { get; set; }
    public BlockType Type { get; set; }
}

public class LiveBlock : Block
{
    public LiveBlock() : base(BlockType.Live) { }
}

public class UnsequencedBlock : Block
{
    public UnsequencedBlock() : base(BlockType.Unsequenced) { }
}

public class BlockLocation
{
    public Guid Id { get; set; }
    public Guid BlockId { get; set; }
    public Block Block { get; set; }
}

public enum BlockType
{
    None = 0,
    Live,
    Unsequenced
}

我想做的是从Entity Framework映射到Domain实体到子类型，并保留引用，以免堆栈溢出

我的映射是

cfg.CreateMap<Data.Block, Domain.LiveBlock>();
cfg.CreateMap<Data.Block, Domain.UnsequencedBlock>();
cfg.CreateMap<Data.Block, Domain.Block>().PreserveReferences().ConstructUsing((block, context) =>
        {
            if (block.Type == BlockType.Live)
            {
                // This loops until stack overflow
                return context.Mapper.Map<Domain.LiveBlock>(block);
            }

            if (block.Type == BlockType.Unsequenced)
            {
                return context.Mapper.Map<Domain.LiveBlock>(block);
            }

            return context.Mapper.Map<Domain.Block>(block);
        });

 cfg.CreateMap<Data.BlockLocation, Domain.BlockLocation>();

我正在尝试执行以下操作：

// This is the EF entity
var block = new Data.Block
{
    Id = Guid.NewGuid(),
    Type = BlockType.Live,
    BlockLocations = new List<Data.BlockLocation>
    {
        new BlockLocation {Id = Guid.NewGuid()},
        new BlockLocation {Id = Guid.NewGuid()}
    }
};

block.BlockLocations[0].Block = block;
block.BlockLocations[1].Block = block;

// Trying to create a Domain entity
var domainBlock = Mapper.Map<Data.Block, Domain.Block>(block);

我想要实现的结果是 domainBlock 的类型为LiveBlock，并具有BlockLocations列表，这些BlockLocations的LiveBlock实体与其 Block 属性相同

我得到的是ConstructUsing中的一个循环，直到出现堆栈溢出。

现在，我的问题是：

这可以通过AutoMapper实现吗？
如果是，可以使用ContructUsing完成吗？我也尝试过ConvertUsing，但得到的结果相同。
也许还有其他方法吗？

我知道一种解决方法是忽略 Domain.Block 中的 BlockLocations 属性，并分别映射它们，但我想为此使用Automapper自动。

谢谢您的帮助。

Answer 1

在Lucian的帮助下使其正常工作

我将映射器更改为以下

cfg.CreateMap<Data.Block, Domain.LiveBlock>().PreserveReferences();
cfg.CreateMap<Data.Block, Domain.UnsequencedBlock>().PreserveReferences();
cfg.CreateMap<Data.Block, Domain.Block>().PreserveReferences().ConstructUsing((block, context) =>
    {
        if (block.Type == BlockType.Live)
        {
            var b = new LiveBlock();
            return context.Mapper.Map(block, b, context);
        }

        if (block.Type == BlockType.Unsequenced)
        {
            var unsequencedBlock = new UnsequencedBlock();
            return context.Mapper.Map(block, unsequencedBlock, context);
        }

        return context.Mapper.Map<Domain.Block>(block);
    });

cfg.CreateMap<Data.BlockLocation, Domain.BlockLocation>().PreserveReferences();

secred是使用以上下文为参数的Map方法

context.Mapper.Map(block, unsequencedBlock, context);

AutoMapper-继承保留引用

1 个答案: