Question

我想使用以下内容将业务对象的分页列表映射到视图模型对象的分页列表：

var listViewModel = _mappingEngine.Map<IPagedList<RequestForQuote>, IPagedList<RequestForQuoteViewModel>>(requestForQuotes);

分页列表实现类似于Rob Conery的实现： http://blog.wekeroad.com/2007/12/10/aspnet-mvc-pagedlistt/

如何设置Automapper来执行此操作？

Answer 1

使用jrummell的答案，我创建了一个与Troy Goode's PagedList一起使用的扩展方法。它使您不必在任何地方放置如此多的代码......

    public static IPagedList<TDestination> ToMappedPagedList<TSource, TDestination>(this IPagedList<TSource> list)
    {
        IEnumerable<TDestination> sourceList = Mapper.Map<IEnumerable<TSource>, IEnumerable<TDestination>>(list);
        IPagedList<TDestination> pagedResult = new StaticPagedList<TDestination>(sourceList, list.GetMetaData());
        return pagedResult;

    }

用法是：

var pagedDepartments = database.Departments.OrderBy(orderBy).ToPagedList(pageNumber, pageSize).ToMappedPagedList<Department, DepartmentViewModel>();

Answer 2

AutoMapper不支持开箱即用，因为它不知道IPagedList<>的任何实现。但是你有几个选择：

使用现有的Array / EnumerableMappers作为指南编写自定义IObjectMapper。这就是我个人的方式。

使用：

编写自定义TypeConverter

Mapper
    .CreateMap<IPagedList<Foo>, IPagedList<Bar>>()
    .ConvertUsing<MyCustomTypeConverter>();

并在内部使用Mapper.Map来映射列表中的每个元素。

Answer 3

如果您使用的是Troy Goode's PageList，则可以使用StaticPagedList课程来帮助您进行映射。

// get your original paged list
IPagedList<Foo> pagedFoos = _repository.GetFoos(pageNumber, pageSize);
// map to IEnumerable
IEnumerable<Bar> bars = Mapper.Map<IEnumerable<Bar>>(pagedFoos);
// create an instance of StaticPagedList with the mapped IEnumerable and original IPagedList metadata
IPagedList<Bar> pagedBars = new StaticPagedList<Bar>(bars, pagedFoos.GetMetaData());

Answer 4

我在AutoMapper周围创建了一个小包装，将PagedList<DomainModel>映射到PagedList<ViewModel>。

public class MappingService : IMappingService
{
    public static Func<object, Type, Type, object> AutoMap = (a, b, c) =>
    {
        throw new InvalidOperationException(
            "The Mapping function must be set on the MappingService class");
    };

    public PagedList<TDestinationElement> MapToViewModelPagedList<TSourceElement, TDestinationElement>(PagedList<TSourceElement> model)
    {
        var mappedList = MapPagedListElements<TSourceElement, TDestinationElement>(model);
        var index = model.PagerInfo.PageIndex;
        var pageSize = model.PagerInfo.PageSize;
        var totalCount = model.PagerInfo.TotalCount;

        return new PagedList<TDestinationElement>(mappedList, index, pageSize, totalCount);
    }

    public object Map<TSource, TDestination>(TSource model)
    {
        return AutoMap(model, typeof(TSource), typeof(TDestination));
    }

    public object Map(object source, Type sourceType, Type destinationType)
    {
        if (source is IPagedList)
        {
            throw new NotSupportedException(
                "Parameter source of type IPagedList is not supported. Please use MapToViewModelPagedList instead");
        }

        if (source is IEnumerable)
        {
            IEnumerable<object> input = ((IEnumerable)source).OfType<object>();
            Array a = Array.CreateInstance(destinationType.GetElementType(), input.Count());

            int index = 0;
            foreach (object data in input)
            {
                a.SetValue(AutoMap(data, data.GetType(), destinationType.GetElementType()), index);
                index++;
            }
            return a;
        }

        return AutoMap(source, sourceType, destinationType);
    }

    private static IEnumerable<TDestinationElement> MapPagedListElements<TSourceElement, TDestinationElement>(IEnumerable<TSourceElement> model)
    {
        return model.Select(element => AutoMap(element, typeof(TSourceElement), typeof(TDestinationElement))).OfType<TDestinationElement>();
    }
}

用法：

PagedList<Article> pagedlist = repository.GetPagedList(page, pageSize);
mappingService.MapToViewModelPagedList<Article, ArticleViewModel>(pagedList);

您必须使用元素类型！

如果您有任何问题或建议，请随时评论：）

Answer 5

AutoMapper自动处理多种类型的列表和数组之间的转换： http://automapper.codeplex.com/wikipage?title=Lists%20and%20Arrays

它似乎不会自动转换从IList继承的自定义类型的列表，但解决方法可能是：

    var pagedListOfRequestForQuote = new PagedList<RequestForQuoteViewModel>(
        AutoMapper.Mapper.Map<List<RequestForQuote>, List<RequestForQuoteViewModel>>(((List<RequestForQuote>)requestForQuotes),
        page ?? 1,
        pageSize

Answer 6

我需要使用AutoMapper版本6.0.2返回IPagedList<>的可序列化版本，该版本支持ASP.NET Web API的IMapper接口。所以，如果问题是我如何支持以下内容：

//Mapping from an enumerable of "foo" to a different enumerable of "bar"...
var listViewModel = _mappingEngine.Map<IPagedList<RequestForQuote>, PagedViewModel<RequestForQuoteViewModel>>(requestForQuotes);

然后就可以做到这一点：

定义PagedViewModel<T>
来源：AutoMapper Custom Type Converter not working

public class PagedViewModel<T>
{
    public int FirstItemOnPage { get; set; }
    public bool HasNextPage { get; set; }
    public bool HasPreviousPage { get; set; }
    public bool IsFirstPage { get; set; }
    public bool IsLastPage { get; set; }
    public int LastItemOnPage { get; set; }
    public int PageCount { get; set; }
    public int PageNumber { get; set; }
    public int PageSize { get; set; }
    public int TotalItemCount { get; set; }
    public IEnumerable<T> Subset { get; set; }
}

将开放式通用转换器从IPagedList<T>写入PagedViewModel<T>
来源：https://github.com/AutoMapper/AutoMapper/wiki/Open-Generics

public class Converter<TSource, TDestination> : ITypeConverter<IPagedList<TSource>, PagedViewModel<TDestination>>
{
    public PagedViewModel<TDestination> Convert(IPagedList<TSource> source, PagedViewModel<TDestination> destination, ResolutionContext context)
    {
        return new PagedViewModel<TDestination>()
        {
            FirstItemOnPage = source.FirstItemOnPage,
            HasNextPage = source.HasNextPage,
            HasPreviousPage = source.HasPreviousPage,
            IsFirstPage = source.IsFirstPage,
            IsLastPage = source.IsLastPage,
            LastItemOnPage = source.LastItemOnPage,
            PageCount = source.PageCount,
            PageNumber = source.PageNumber,
            PageSize = source.PageSize,
            TotalItemCount = source.TotalItemCount,
            Subset = context.Mapper.Map<IEnumerable<TSource>, IEnumerable<TDestination>>(source) //User mapper to go from "foo" to "bar"
        };
    }
}

配置映射器

new MapperConfiguration(cfg =>
    {
        cfg.CreateMap<RequestForQuote, RequestForQuoteViewModel>();//Define each object you need to map
        cfg.CreateMap(typeof(IPagedList<>), typeof(PagedViewModel<>)).ConvertUsing(typeof(Converter<,>)); //Define open generic mapping
    });

Automapper可以映射分页列表吗？

6 个答案: