AutoMapper 在验证期间抛出 "No default constructor"

Question

我要映射类，但它们没有默认构造函数，我也不希望它们有。这是因为我只映射 to/from 个已经存在的对象。

public class Order
{
    public string OrderName { get; set; }
    public Order(string name) 
    { 
        this.OrderName = name; 
    }
}

public class OrderProcessor
{
    private IService service;
    public string OrderName { get; set; }

    public OrderProcessor(IService service)
    { 
        this.service = service; 
        Mapper.Initialize(config => config.CreateMap<Order, OrderProcessor>());
    }

    public void Init()
    { 
        var order = this.service.GetOrder();

        // this works
        Mapper.Map(order, this);

        // this fails
        Mapper.Configuration.AssertConfigurationIsValid();
    }
}

AutoMapper.AutoMapperConfigurationException : Unmapped members were found. Review the types and members below. Add a custom mapping expression, ignore, add a custom resolver, or modify the source/destination type For no matching constructor, add a no-arg ctor, add optional arguments, or map all of the constructor parameters

Order -> OrderProcessor (Destination member list)

No available constructor.

at Test() in Tests.cs:line

当我不想创建新对象时，如何使配置断言通过以及为什么它会失败？

Answer 1

您需要使用 .ConstructUsing()，因为您的类型没有无参数构造函数...

类似的东西；

 Mapper.Initialize(config => 
    config.CreateMap<Order, OrderProcessor>()
    .ConstructUsing(x => new OrderProcessor(new WhateverService()));
);

您可能显然需要使用您正在使用的任何 DI 框架来解析 WhateverService....

Answer 2

我最近从 Automapper 4.x 升级到 6.x 后也遇到了这个问题。

您需要通过调用 CreateMap<TSource, TDest>().DisableCtorValidation().

告诉 AutoMapper 您不打算让它构造目标类型

根据方法文档：

    // Summary:
    //     Disable constructor validation. During mapping this map is used 
    //     against an existing destination object and never constructed itself.
    //

AutoMapper 在验证期间抛出 "No default constructor"

AutoMapper throwing "No default constructor" during validation

.net

c#

automapper

automapper-5