如何更新从视图模型使用Automapper和EF4的DbContext与延迟加载启用一个现有实体 [英] How to update an existing Entity from ViewModel using Automapper and EF4 DbContext with Lazy Loading enabled

问题描述

我使用Automapper到实体和视图模型对象（双向）之间进行映射。该模型使用EF4的DbContext波苏斯，需要惰性加载（因此代理代）启用。

我所遇到试图更新从视图模型现有实体的一个问题。当我打电话Mapper.Map（VM，实体），Automapper抛出异常。我的问题是：怎么是你应该使用Automapper EF代理对象的工作。

在code相（简体）是这样的：

 公共类myEntity所
{
    公众诠释标识{获取;设置;}
    公众诠释名称{;设置;}
}公共类视图模型
{
    公众诠释标识{获取;设置;}
    公众诠释名称{;设置;}
}Mapper.CreateMap＆LT; myEntity所，视图模型＆GT;（）;
Mapper.CreateMap＆LT;视图模型，myEntity所＆GT;（）;公众的ActionResult编辑（视图模型VM）
{
    myEntity所实体= db.MyEntities.Find（vm.Id）;
    Mapper.Map（VM，实体）;
    db.Entry（实体）.STATE = EntityState.Modified;
    db.SaveChanges（）;
}
 

当我打电话Mapper.Map（VM，实体）更新现有的实体对象，我得到异常：

 'Mapper.Map（视图模型，的resultSet）'扔类型的异常AutoMapper.AutoMapperMappingException
基地的System.Exception {}：{缺少类型映射配置或不支持的映射\\ n \\ nMapping类型：\\ r \\ nResultSetView  - 方式＆gt; ResultSet_692D75838D4DC59B922F3E88CF1B10516CBF6CD8A32C4BE2F3FCC28CE83F0BD2\\r\
Sciensus.Applications.ClinicalStudies.Web.Areas.Patient.Models.ResultSetView - ＆GT; System.Data.Entity.DynamicProxies.ResultSet_692D75838D4DC59B922F3E88CF1B10516CBF6CD8A32C4BE2F3FCC28CE83F0BD2\
\
Destination路径：\\ nResultSet_692D75838D4DC59B922F3E88CF1B10516CBF6CD8A32C4BE2F3FCC28CE83F0BD2 \\ n \\ n源值：\\ nSciensus.Applications.ClinicalStudies.Web.Areas.Patient.Models.ResultSetView}
语境：{试图ResultSetView映射到ResultSet_692D75838D4DC59B922F3E88CF1B10516CBF6CD8A32C4BE2F3FCC28CE83F0BD2。}
。消息：缺少类型映射配置或不支持的映射\\ n \\ nMapping类型：\\ r \\ nResultSetView  - ＆GT; ResultSet_692D75838D4DC59B922F3E88CF1B10516CBF6CD8A32C4BE2F3FCC28CE83F0BD2\\r\
Sciensus.Applications.ClinicalStudies.Web.Areas.Patient.Models.ResultSetView - ＆GT; System.Data.Entity.DynamicProxies.ResultSet_692D75838D4DC59B922F3E88CF1B10516CBF6CD8A32C4BE2F3FCC28CE83F0BD2\
\
Destination路径：\\ nResultSet_692D75838D4DC59B922F3E88CF1B10516CBF6CD8A32C4BE2F3FCC28CE83F0BD2 \\ n \\ n源值：\\ nSciensus.Applications.ClinicalStudies.Web.Areas.Patient.Models.ResultSetView
堆栈跟踪： 
 

解决方案

我看了看AutoMapper源$ C ​​$ C：

 公共TDestination地图＆LT; TSource，TDestination＆GT;（TSource源，TDestination目的地）
    {
        返回地图（源，目标，选择采用= GT; {}）;
    }    公共TDestination地图＆LT; TSource，TDestination＆GT;（TSource源，TDestination目的地，动作＆LT; IMappingOperationOptions＆GT;选择采用）
    {
        键入modelType = typeof运算（TSource）;
        类型destinationType =（等号（目的地，默认（TDestination））的typeof（TDestination）：destination.GetType（））;        回报（TDestination）地图（源，目标，modelType，destinationType，选择采用）;
    }
 

问题发生在这个地方：

 键入destinationType =（等号（目的地，默认（TDestination））的typeof（TDestination）：destination.GetType（））;
 

，这样才不会有问题的变化：

  Mapper.Map（VM，实体的typeof（视图模型）的typeof（myEntity所））;
 

I am using Automapper to map between Entity and ViewModel object (in both directions). The model uses EF4 DbContext POCOs and needs LazyLoading (and therefore Proxy Generation) enabled.

I have come across a problem attempting to update an existing entity from a viewmodel. When I call Mapper.Map(vm, entity), Automapper throws an exception. My question is: how are you supposed to work with EF Proxy objects using Automapper?

The code looks (simplified) like this:

public class MyEntity
{
    public int Id {get;set;}
    public int Name {get;set;}
}

public class ViewModel
{
    public int Id {get;set;}
    public int Name {get;set;}
}

Mapper.CreateMap<MyEntity, ViewModel>();
Mapper.CreateMap<ViewModel, MyEntity>();

public ActionResult Edit(ViewModel vm)
{
    MyEntity entity = db.MyEntities.Find(vm.Id);
    Mapper.Map(vm, entity);
    db.Entry(entity).State = EntityState.Modified;
    db.SaveChanges();
}

When I call Mapper.Map(vm, entity) to update the existing entity object, I get the exception:

'Mapper.Map(viewModel, resultSet)' threw an exception of type 'AutoMapper.AutoMapperMappingException'
base {System.Exception}: {"Missing type map configuration or unsupported mapping.\n\nMapping types:\r\nResultSetView -> ResultSet_692D75838D4DC59B922F3E88CF1B10516CBF6CD8A32C4BE2F3FCC28CE83F0BD2\r\nSciensus.Applications.ClinicalStudies.Web.Areas.Patient.Models.ResultSetView -> System.Data.Entity.DynamicProxies.ResultSet_692D75838D4DC59B922F3E88CF1B10516CBF6CD8A32C4BE2F3FCC28CE83F0BD2\n\nDestination path:\nResultSet_692D75838D4DC59B922F3E88CF1B10516CBF6CD8A32C4BE2F3FCC28CE83F0BD2\n\nSource value:\nSciensus.Applications.ClinicalStudies.Web.Areas.Patient.Models.ResultSetView"}
Context: {Trying to map ResultSetView to ResultSet_692D75838D4DC59B922F3E88CF1B10516CBF6CD8A32C4BE2F3FCC28CE83F0BD2.}
Message: "Missing type map configuration or unsupported mapping.\n\nMapping types:\r\nResultSetView -> ResultSet_692D75838D4DC59B922F3E88CF1B10516CBF6CD8A32C4BE2F3FCC28CE83F0BD2\r\nSciensus.Applications.ClinicalStudies.Web.Areas.Patient.Models.ResultSetView -> System.Data.Entity.DynamicProxies.ResultSet_692D75838D4DC59B922F3E88CF1B10516CBF6CD8A32C4BE2F3FCC28CE83F0BD2\n\nDestination path:\nResultSet_692D75838D4DC59B922F3E88CF1B10516CBF6CD8A32C4BE2F3FCC28CE83F0BD2\n\nSource value:\nSciensus.Applications.ClinicalStudies.Web.Areas.Patient.Models.ResultSetView"
StackTrace: ""

解决方案

I looked at the AutoMapper source Code:

    public TDestination Map<TSource, TDestination>(TSource source, TDestination destination)
    {
        return Map(source, destination, opts => { });
    }

    public TDestination Map<TSource, TDestination>(TSource source, TDestination destination, Action<IMappingOperationOptions> opts)
    {
        Type modelType = typeof(TSource);
        Type destinationType = (Equals(destination, default(TDestination)) ? typeof(TDestination) : destination.GetType());

        return (TDestination)Map(source, destination, modelType, destinationType, opts);
    }

Problems occurred in this place:

  Type destinationType = (Equals(destination, default(TDestination)) ? typeof(TDestination) : destination.GetType());

So the change that do not have a problem:

  Mapper.Map(vm, entity,typeof(ViewModel),typeof(MyEntity));

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