使用一键地图列表，以现有的列表中Automapper [英] Map list to existing list in Automapper using a key

问题描述

Automapper轻松处理映射到不同的对象类型的另一个列表对象类型的列表，但有可能有它使用ID作为关键字映射到现有列表？

Automapper easily handles mapping one list of object types to another list of different objects types, but is it possible to have it map to an existing list using an ID as a key?

推荐答案

我还没有发现比下面更好的办法。

I have not found better way than the following.

下面是源和目标。

public class Source
{
    public int Id { get; set; } 
    public string Foo { get; set; }
}

public class Destination 
{ 
    public int Id { get; set; }
    public string Foo { get; set; }
}

定义转换器（您应该更改名单，LT ）。

Define converter (You should change List<> to whatever type you are using).

public class CollectionConverter: ITypeConverter<List<Source>, List<Destination>>
{
    public List<Destination> Convert(ResolutionContext context)
    {
        var destinationCollection = (List<Destination>)context.DestinationValue;
        if(destinationCollection == null)
            destinationCollection = new List<Destination>();
        var sourceCollection = (List<Source>)context.SourceValue;
        foreach(var source in sourceCollection)
        {
            Destination matchedDestination = null;

            foreach(var destination in destinationCollection)
            {
                if(destination.Id == source.Id)
                {
                    Mapper.Map(source, destination);
                    matchedDestination = destination;
                    break;
                }
            }
            if(matchedDestination == null)
                destinationCollection.Add(Mapper.Map<Destination>(source));
        }
        return destinationCollection;
    }
}

这是实际的映射配置和榜样。

And here is actual mapping configuration and example.

Mapper.CreateMap<Source,Destination>();
Mapper.CreateMap<List<Source>,List<Destination>>().ConvertUsing(new CollectionConverter());

var sourceCollection = new List<Source>
{
    new Source{ Id = 1, Foo = "Match"},
    new Source{ Id = 2, Foo = "DoesNotMatchWithDestination"}
};
var destinationCollection = new List<Destination>
{
    new Destination{ Id = 1, Foo = "Match"},
    new Destination{ Id = 3, Foo = "DoeNotMatchWithSource"}
};
var mergedCollection = Mapper.Map(sourceCollection, destinationCollection);

您应该得到以下结果。

这篇关于使用一键地图列表，以现有的列表中Automapper的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！