[英]Can Automapper map a paged list?
我想 map 业务对象的分页列表到视图 model 对象的分页列表,使用如下:
var listViewModel = _mappingEngine.Map<IPagedList<RequestForQuote>, IPagedList<RequestForQuoteViewModel>>(requestForQuotes);
分页列表实现类似于 Rob Conery 在这里的实现: http://blog.wekeroad.com/2007/12/10/as.net-mvc-pagedlistt/
您如何设置 Automapper 来执行此操作?
使用jrummell的答案,我创建了一个与Troy Goode的PagedList一起使用的扩展方法。 它让你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>();
AutoMapper不支持开箱即用,因为它不知道IPagedList<>
任何实现。 但是你有两个选择:
使用现有的Array / EnumerableMappers作为指南编写自定义IObjectMapper
。 这是我亲自去的方式。
编写自定义TypeConverter,使用:
Mapper .CreateMap<IPagedList<Foo>, IPagedList<Bar>>() .ConvertUsing<MyCustomTypeConverter>();
并在里面使用Mapper.Map
来映射列表的每个元素。
如果你正在使用Troy Goode的 StaticPagedList
,那么有一个StaticPagedList
类可以帮助你映射。
// 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());
我在AutoMapper周围创建了一个小包装器,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);
重要的是你必须使用元素类型!
如果您有任何问题或建议,请随时评论:)
AutoMapper自动处理几种类型的列表和数组之间的转换: http ://automapper.codeplex.com/wikipage?title = List%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
我需要使用支持ASP.NET Web API的IMapper
接口的AutoMapper版本6.0.2返回可序列化版本的IPagedList<>
。 那么,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);
然后人们可以这样做:
定义PagedViewModel<T>
来源: AutoMapper自定义类型转换器无法正常工作
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>
资料来源: 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 .net core 8.1.1 很容易
您只需要将类型映射添加到您的 mapperProfile 并映射 pagedList 内的对象
CreateMap(typeof(IPagedList<>), typeof(IPagedList<>));
CreateMap<RequestForQuote, RequestForQuoteViewModel>().ReverseMap();
并且您可以直接在 mapper.Map 中使用它 - 在类构造函数中从 IMapper 初始化映射器
RequestForQuote result
_mapper.Map<IPagedList<RequestForQuoteViewModel>>(result);
如果您正在使用 X.PageList 那么您可以简单地使用此代码:
PagedList<exampleDTO> result = new PagedList<exampleDTO>(item, _mapper.Map<List<exampleDTO>>(item.ToList()));
PageList 允许您使用修改后的项目创建新的 PageList。
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