使用AutoMapper展平嵌套列表

问题描述：

我试图在.NET 3.5中将嵌套对象展平为DTO对象.到目前为止，我所看到的大部分内容是使用 AutoMapper 进行此操作(不幸的是，由于我需要使用.NET 3.5，因此使用v1.x):

I'm trying to flatten a nested object into a DTO object in .NET 3.5. Most of what I've seen so far is to use AutoMapper to do this (using v1.x since I need to use .NET 3.5, unfortunately):

这是我的类结构的摘要:

Here's what a snippet of my class structures look like:

public class RootObject
{
    [JsonProperty("BaseSupplier")]
    public BaseSupplier BaseSupplier { get; set; }

    [JsonProperty("BaseOrderShipmentLineitem")]
    public IList<BaseOrderShipmentLineitem> BaseOrderShipmentLineitem { get; set; }
}

public class BaseSupplier
{
    [JsonProperty("id")]
    public int Id { get; set; }

    [JsonProperty("name")]
    public string Name { get; set; }
}

public class BaseOrderShipmentLineitem
{
    [JsonProperty("id")]
    public int Id { get; set; }

    [JsonProperty("qty_delivered")]
    public int QtyDelivered { get; set; }

    [JsonProperty("BaseOrderLineitem")]
    public BaseOrderLineitem BaseOrderLineitem { get; set; }    
}

public class BaseOrderLineitem
{
    [JsonProperty("id")]
    public int Id { get; set; }

    [JsonProperty("product_sku")]
    public string ProductSku { get; set; }
}

public class ShipmentDetailsDTO
{
    public int BaseOrderShipmentLineitemId { get; set; }
    public string BaseSupplierName { get; set; }
    public string Sku { get; set; }
}

我一直在尝试这样的事情:

I've been trying something like this:

Mapper.CreateMap<BaseOrderLineitem, ShipmentDetailsDTO>()
    .ForMember(d => d.Sku, opts => opts.MapFrom(s => s.ProductSku));
Mapper.CreateMap<BaseOrderShipmentLineitem, ShipmentDetailsDTO>();
Mapper.CreateMap<RootObject, ShipmentDetailsDTO>()
    .ForMember(d => d.Sku, opts => opts.MapFrom(s => Mapper.Map<IEnumerable<BaseOrderLineitem>, IEnumerable<ShipmentDetailsDTO>>(s.BaseOrderShipmentLineitem.SelectMany(q => q.BaseOrderLineitem)).FirstOrDefault().Sku))
    ;

var model = Mapper.Map<IEnumerable<RootObject>, IEnumerable<ShipmentDetailsDTO>>(obj);

使用上面的代码，我在此问题上出错了. s.BaseOrderShipmentLineitem.SelectMany(q => q.BaseOrderLineitem):

With that above code I'm getting an error on this bit s.BaseOrderShipmentLineitem.SelectMany(q => q.BaseOrderLineitem):

Cannot implicitly convert type 'IEnumerable<?>' to 'IEnumerable<BaseOrderLineitem>'. An explicit conversion exists (are you missing a cast?)

我不确定这是否只是我忽略的简单事物.

I'm not sure if it's something simple I'm just overlooking or not.

答

一种简单得多的方法是使用LINQ编写一个简单的扩展方法来自己进行投影.更简单，更透明:

A far easier way is to write a simple extension method using some LINQ to do this projection yourself. It's easier and more transparent:

public static class MyConversionExtensions
{
    public static IEnumerable<ShipmentDetailsDTO> ToShipmentDetails(this RootObject root)
    {
        return root.BaseOrderShipmentLineitem.Select(x => new ShipmentDetailsDTO() {
            BaseOrderShipmentLineitemId = x.BaseOrderLineitem.Id,
            BaseSupplierName = root.BaseSupplier.Name,
            Sku = x.BaseOrderLineitem.ProductSku
        });
    }
}

用法:

var shipmentDetails = myRootObject.ToShipmentDetails();

使用AutoMapper展平嵌套列表

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