如何通用Automapper Config

Question

我使用 Automapper 版本 4.2.0 并且我都 Action Methods 我有这样的设置 :

  var attributeGroups = _attributeGroupService.AttributeGroupDropdown();
        var mapconfiguration = new MapperConfiguration(cfg => cfg.CreateMap<AttributeGroup, AttributeGroupViewModel>());
        var mapper = mapconfiguration.CreateMapper();
        var result = mapper.Map(attributeGroups, new List<AttributeGroupViewModel>());

我不会在所有操作中重复此代码，我想创建一个通用方法并将数据传递给它并映射它，为此，我创建了一个这样的方法吗？

 public N mapping<T,K,M,N>(T resource, K destination,M model,N newModel) 
    {
        var mapconfiguration = new MapperConfiguration(cfg => cfg.CreateMap<T, K>());
        var mapper = mapconfiguration.CreateMapper();
        var result = mapper.Map<M,N>(model, newModel);
        return result;
    }

并这样称呼它：

var ResultTest=mapping<AttributeGroup,AttributeGroupViewModel,attributeGroups,new List<AttributeGroupViewModel>()>();

但它不符合。

我该怎么做？

Answer 1

简短回答：您需要在泛型参数列表中提供类型，在函数调用的参数列表中提供变量。此外，您根本不需要 T resource, K destination 参数，因为它们未被使用。

你的方法还有一个问题，使用起来不是很方便。所以我建议你提供两种降低复杂性的专门方法。

请参阅下面的完整示例。它包含方法 mapAnything<...>，它与您的 mapping<...> 方法等效。方法 mapObject<...> 和 mapCollection<...> 是我所说的专门方法。

class TestResource
{
    public int Testnumber { get; set; }
    public string Testtext { get; set; }
}

class TestDestination
{
    public string Testtext { get; set; }
}

class Program
{
    // equivalent to what you tried to do - needs explicit generic parameters on call
    static N mapAnything<T, K, M, N>(M model, N newModel)
    {
        var mapconfiguration = new MapperConfiguration(cfg => cfg.CreateMap<T, K>());
        var mapper = mapconfiguration.CreateMapper();
        var result = mapper.Map<M, N>(model, newModel);
        return result;
    }

    // variant for object mapping, where generics can be implicitely inferred
    static N mapObject<M, N>(M model, N newModel)
    {
        var mapconfiguration = new MapperConfiguration(cfg => cfg.CreateMap<M, N>());
        var mapper = mapconfiguration.CreateMapper();
        var result = mapper.Map<M, N>(model, newModel);
        return result;
    }

    // variant for lists, where generics can be implicitely inferred
    static ICollection<N> mapCollection<M, N>(IEnumerable<M> model, ICollection<N> newModel)
    {
        var mapconfiguration = new MapperConfiguration(cfg => cfg.CreateMap<M, N>());
        var mapper = mapconfiguration.CreateMapper();
        var result = mapper.Map<IEnumerable<M>, ICollection<N>>(model, newModel);
        return result;
    }

    static void Main(string[] args)
    {
        var res1 = new TestResource() { Testnumber = 1, Testtext = "a" };
        var res2 = new List<TestResource>();
        for (int i = 0; i < 10; i++)
        {
            res2.Add(new TestResource() { Testnumber = i, Testtext = "test: " + i });
        }
        var mapped1 = mapObject(res1, new TestDestination());
        var mapped2 = mapCollection(res2, new HashSet<TestDestination>());
        var mapped3 = mapAnything<TestResource, TestDestination, TestResource, TestDestination>(res1, new TestDestination());
        var mapped4 = mapAnything<TestResource, TestDestination, IEnumerable<TestResource>, List<TestDestination>>(res2, new List<TestDestination>());
    }
}

如何通用Automapper Config

how to generic Automapper Config

c#

generics

automapper