类型的异常“AutoMapper.AutoMapperMappingException”发生在AutoMapper.dll但在用户code没有处理 [英] An exception of type 'AutoMapper.AutoMapperMappingException' occurred in AutoMapper.dll but was not handled in user code

问题描述

不知怎的，我的code不工作了（它确实具有完全相同的code工作之前）。这就是问题：

的code

我想一定对象的ViewModels这个code图：

配置：

  Mapper.CreateMap＆LT; BookcaseItem，FoundBookcaseItemViewModel＆GT;（）
    .ForMember（X =＆GT; x.Title，选择=＆GT; opt.MapFrom（SRC =＆GT; src.Book.Title））
    .ForMember（X =＆GT; x.Authors，停用= GT; opt.MapFrom（SRC =＆GT; src.Book.Authors.Select（X =＆GT; x.Name）.Aggregate（（I，J）=＆GT; I +，+ J）））
    .ForMember（X =＆GT; x.Identifiers，选择=＆GT; opt.MapFrom（SRC =＆GT;（string.IsNullOrEmpty（src.Book.Isbn10）（ISBN10：？+ src.Book.Isbn10 +\\ r \\ N）的String.Empty）+
                                                                （string.IsNullOrEmpty（src.Book.Isbn13）（哲学，！？+ src.Book.Isbn13）的String.Empty）））
    .ForMember（X =＆GT; x.Pages，选择=＆GT; opt.MapFrom（SRC =＆GT; src.Book.Pages））
    .ForMember（X =＆GT; x.ImageUri，选择=＆GT; opt.MapFrom（SRC =＆GT; src.Book.ThumbnailUriSmall））;
 

用法：

 公众的ActionResult指数（）
{
    字符串facebookId = _accountService.GetLoggedInUserFacebookId（）;    IEnumerable的＆LT; BookcaseItem＆GT;项目= _bookcaseItemService.GetBookcaseItemsForUser（facebookId）;
    IEnumerable的＆LT; FoundBookcaseItemViewModel＆GT;的ViewModels = items.Select（Mapper.Map＆LT; BookcaseItem，FoundBookcaseItemViewModel＆GT;）;    返回PartialView（的ViewModels）;
}
 

错误

这将导致以下错误：

  

类型的异常AutoMapper.AutoMapperMappingException发生在AutoMapper.dll但在用户code没有处理

调试数据

首先我保证不存在任何配置错误，通过调用：

  Mapper.AssertConfigurationIsValid（）;
 

我已经设置断点都在我的code和尝试调试它，但我无法理解它。在项目集合填充数据（由实体框架生成的代理类），但在'的ViewModels收集充满了奇怪的数据。它有说这是一个消息：

  

映射类型：
  BookcaseItem_B9B52593B2659AC05​​C47AB2A6E0F7AEA9989CC34D3527DF5B6AA988ED57166FB
   - >字符串System.Data.Entity.DynamicProxies.BookcaseItem_B9B52593B2659AC05C47AB2A6E0F7AEA9989CC34D3527DF5B6AA988ED57166FB
   - > System.String

  
  

目标路径：FoundBookcaseItemViewModel.Authors

  
  

来源值：
  System.Data.Entity.DynamicProxies.BookcaseItem_B9B52593B2659AC05C47AB2A6E0F7AEA9989CC34D3527DF5B6AA988ED57166FB

再有就是，说一个堆栈跟踪属性：

  

在System.Linq.Enumerable.WhereSelectEnumerableIterator`2.MoveNext（）

  
  

在System.Linq.SystemCore_EnumerableDebugView`1.get_Items（）

呵呵，终于有一个名为语境具有下列数据的属性：

谁能解释一下是怎么回事，为什么我的code工作不下去了？我做了一些更改，以我的解决方案最近，但我滚回去用Git的，所以他们不应该对code任何影响。

我的设置

• 的Visual Studio 12 RC


• ASP.NET MVC 4


• 的.NET Framework 4.0（我有4.5，但导致了太多的错误，所以我使用Git回滚到4.0版本）


• 实体框架5.0 RC


• AutoMapper 2.1.267

实体和视图模型

我不知道这是否是相关的，但这里是该映射的源类：

 公共类BookcaseItem：实体
{
    公众的Guid标识{搞定;组; }
    公共BOOL IsRenting {搞定;组; }
    公共BOOL IsSwapping {搞定;组; }
    公共BOOL IsSelling {搞定;组; }
    公共小数RentingPrice {搞定;组; }
    公共小数SellingPrice {搞定;组; }
    公共字符串货币{搞定;组; }
    公共BOOL IsAvailable {搞定;组; }
    公共虚拟的Guid BOOKID {搞定;组; }
    公共虚拟的Guid用户Id {搞定;组; }    公共虚拟书书{搞定;组; }
    公共虚拟用户用户{搞定;组; }    公共BookcaseItem（）
    {
        IsAvailable = TRUE;
        货币=USD;
    }
}
 

这是该映射的目标类：

 公共类FoundBookcaseItemViewModel
{
    公众的Guid标识{搞定;组; }
    公共BOOL IsRenting {搞定;组; }
    公共BOOL IsSwapping {搞定;组; }
    公共BOOL IsSelling {搞定;组; }
    公共小数RentingPrice {搞定;组; }
    公共小数SellingPrice {搞定;组; }
    公共字符串名称{搞定;组; }
    公共字符串作者{搞定;组; }
    公共字符串标识符{搞定;组; }
    公众诠释页{搞定;组; }
    公共字符串ImageUri {搞定;组; }
}
 

解决方案

好像有一个与映射Authors属性的一个问题。如果作者顺序为null或空此汇总调用会抛出异常。

  .ForMember（X =＆GT; x.Authors，
           选择=＆GT; opt.MapFrom（SRC =＆GT; src.Book.Authors.Select（X =＆GT; x.Name）.Aggregate（（I，J）= I标记+，+ J）））
 

Somehow my code doesn't work any more (it did work before with the exact same code). This is the problem:

The code

I'm trying to map some objects to ViewModels with this code:

Configuration:

Mapper.CreateMap<BookcaseItem, FoundBookcaseItemViewModel>()
    .ForMember(x => x.Title, opt => opt.MapFrom(src => src.Book.Title))
    .ForMember(x => x.Authors, opt => opt.MapFrom(src => src.Book.Authors.Select(x => x.Name).Aggregate((i, j) => i + ", " + j)))
    .ForMember(x => x.Identifiers, opt => opt.MapFrom(src => (!string.IsNullOrEmpty(src.Book.Isbn10) ? ("ISBN10: " + src.Book.Isbn10 + "\r\n") : string.Empty) +
                                                                (!string.IsNullOrEmpty(src.Book.Isbn13) ? ("ISBN13: " + src.Book.Isbn13) : string.Empty)))
    .ForMember(x => x.Pages, opt => opt.MapFrom(src => src.Book.Pages))
    .ForMember(x => x.ImageUri, opt => opt.MapFrom(src => src.Book.ThumbnailUriSmall));

The usage:

public ActionResult Index()
{
    string facebookId = _accountService.GetLoggedInUserFacebookId();

    IEnumerable<BookcaseItem> items = _bookcaseItemService.GetBookcaseItemsForUser(facebookId);
    IEnumerable<FoundBookcaseItemViewModel> viewModels = items.Select(Mapper.Map<BookcaseItem, FoundBookcaseItemViewModel>);

    return PartialView(viewModels);
}

The error

This results in the following error:

An exception of type 'AutoMapper.AutoMapperMappingException' occurred in AutoMapper.dll but was not handled in user code

The debug data

First of all I ensure that there are no configuration errors by calling:

Mapper.AssertConfigurationIsValid();

I've set breakpoints all over my code and try to debug it, but I can't make sense of it. The 'items' collection is filled with data (proxy classes generated by Entity Framework), but the the 'viewModels' collection is filled with strange data. It has a 'message' that says this:

Mapping types: BookcaseItem_B9B52593B2659AC05C47AB2A6E0F7AEA9989CC34D3527DF5B6AA988ED57166FB -> String System.Data.Entity.DynamicProxies.BookcaseItem_B9B52593B2659AC05C47AB2A6E0F7AEA9989CC34D3527DF5B6AA988ED57166FB -> System.String

Destination path: FoundBookcaseItemViewModel.Authors

Source value: System.Data.Entity.DynamicProxies.BookcaseItem_B9B52593B2659AC05C47AB2A6E0F7AEA9989CC34D3527DF5B6AA988ED57166FB

And then there's a stacktrace property that says:

at System.Linq.Enumerable.WhereSelectEnumerableIterator`2.MoveNext()

at System.Linq.SystemCore_EnumerableDebugView`1.get_Items()

Oh and finally there's another property called 'context' with the following data:

Can anyone explain what's going on here and why my code isn't working any longer? I did a couple of changes to my solution recently, but I've rolled them back by Git, so they shouldn't have any effect on the code.

My setup

• Visual Studio 12 RC
• ASP.NET MVC 4
• .NET Framework 4.0 (I had 4.5 but that caused too many errors, so I rolled back with Git to version 4.0)
• Entity Framework 5.0 RC
• AutoMapper 2.1.267

The entity and ViewModel

I don't know if it's relevant, but here is the source class for the mapping:

public class BookcaseItem : Entity
{
    public Guid Id { get; set; }
    public bool IsRenting { get; set; }
    public bool IsSwapping { get; set; }
    public bool IsSelling { get; set; }
    public decimal RentingPrice { get; set; }
    public decimal SellingPrice { get; set; }
    public string Currency { get; set; }
    public bool IsAvailable { get; set; }
    public virtual Guid BookId { get; set; }
    public virtual Guid UserId { get; set; }

    public virtual Book Book { get; set; }
    public virtual User User { get; set; }

    public BookcaseItem()
    {
        IsAvailable = true;
        Currency = "USD";
    }
}

And this is the destination class for the mapping:

public class FoundBookcaseItemViewModel
{
    public Guid Id { get; set; }
    public bool IsRenting { get; set; }
    public bool IsSwapping { get; set; }
    public bool IsSelling { get; set; }
    public decimal RentingPrice { get; set; }
    public decimal SellingPrice { get; set; }
    public string Title { get; set; }
    public string Authors { get; set; }
    public string Identifiers { get; set; }
    public int Pages { get; set; }
    public string ImageUri { get; set; }
}

解决方案

It seems like there is a problem with mapping Authors property. This Aggregate call will throw an exception if the Authors sequence is null or empty.

.ForMember(x => x.Authors, 
           opt => opt.MapFrom(src => src.Book.Authors.Select(x => x.Name).Aggregate((i, j) => i + ", " + j)))

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