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[英]How can I use Automapper to map an object to an unknown destination type?
[英]How can I use Automapper to assign values to fields in destination model but not in source model?
我正在将Automapper悬挂在ASP.NET MVC 5应用程序中,目的是将域模型映射到ViewModel。 在某些情况下,我仍然不知道如何解决:当ViewModel(目标)具有不在域模型(源)中的属性时。
ViewModel中的两个附加属性是我需要在Controller中填充的IEnumerables。
正如我在Controller块中的注释(如下所示)中所解释的那样,域模型是源模型,并将被馈送到View表中。 ViewModel中另外两个IEnumerables将填充HTML.BeginForm()
块中的DropDownLists。
我使用.CreateMap<>().ForMember()
看到的示例处理源模型中属性的计算或转换,而不是这种情况,我在其中基于Action参数在控制器中定义某些内容。
我的问题是如何映射控制器中定义的其余IEnumerables?
App_Start中的映射配置
public static class MappingConfig
{
public static void RegisterMaps()
{
AutoMapper.Mapper.Initialize(config =>
{
config.CreateMap<StudentRoster, StudentRosterViewModel>();
});
}
}
模型和视图模型:
[Table("StudentRoster")]
public partial class StudentRoster
{
public int ID { get; set; }
[Required]
[StringLength(3)]
public string Campus { get; set; }
[Required]
[StringLength(4)]
public string FiscalYear { get; set; }
[Required]
[StringLength(50)]
public string StudentName { get; set; }
public int StudentID { get; set; }
}
// ViewModel
public partial class StudentRosterViewModel
{
// Automapper successfully mappped the first five fields
// to the parent class
public int ID { get; set; }
public string Campus { get; set; }
public string FiscalYear { get; set; }
public string StudentName { get; set; }
public int StudentID { get; set; }
// These two fields are not in the parent class
public IEnumerable<SelectListItem> CampusListSelect { get; set; }
public IEnumerable<SelectListItem> FiscalYearSelect { get; set; }
}
控制器中的索引操作:
// GET: StudentRosterViewModels
public ActionResult Index(string campus = "MRA", string fy="FY16")
{
IEnumerable<StudentRoster> query = db.StudentRosters.Where(m=>m.Campus==campus).ToList();
// This successfully maps the domain model to the viewmodel
// This IEnumerable will display in the "Table"
IEnumerable<StudentRosterViewModel> mappedQuery =
AutoMapper.Mapper.Map<IEnumerable<StudentRoster>, IEnumerable<StudentRosterViewModel>>(query);
// The two remaining IEnumerables need to be mapped to 'mappedQuery'
// CampusListSelect and FiscalYearSelect
// These two IEnumerables will populate the dropdownlists in Html.BeginForm()
IEnumerable<SelectListItem> CampusList = new SelectList(new List<string> { "CRA", "DRA", "MRA", "PRA" }, campus);
IEnumerable<SelectListItem> FiscalYearList = new SelectList(new List<string> { "FY12", "FY13", "FY14", "FY15", "FY16" }, fy);
return View(mappedQuery.ToList());
}
您可以尝试使用DynamicMap
填充项目,而无需创建其他映射类。
如果您使用的是旧版本的AutoMapper
(4.1或更低版本),则可以尝试以下操作:
// GET: StudentRosterViewModels
public ActionResult Index(string campus = "MRA", string fy="FY16")
{
IEnumerable<StudentRoster> query = db.StudentRosters.Where(m=>m.Campus==campus).ToList();
// This successfully maps the domain model to the viewmodel
// This IEnumerable will display in the "Table"
IEnumerable<StudentRosterViewModel> mappedQuery =
AutoMapper.Mapper.Map<IEnumerable<StudentRoster>, IEnumerable<StudentRosterViewModel>>(query);
// The two remaining IEnumerables need to be mapped to 'mappedQuery'
// CampusListSelect and FiscalYearSelect
// These two IEnumerables will populate the dropdownlists in Html.BeginForm()
IEnumerable<SelectListItem> CampusList = new SelectList(new List<string> { "CRA", "DRA", "MRA", "PRA" }, campus);
IEnumerable<SelectListItem> FiscalYearList = new SelectList(new List<string> { "FY12", "FY13", "FY14", "FY15", "FY16" }, fy);
var objForDynamicMapping = new
{
CampusListSelect = CampusList,
FiscalYearListSelect = FiscalYearList
};
foreach(var mappedItem in mappedQuery)
{
// will create the mapping configuration dynamically
AutoMapper.Mapper.DynamicMap(objForDynamicMapping, mappedItem);
}
return View(mappedQuery.ToList());
}
如果您使用的是AutoMapper 4.2或更高版本。
然后,您只需要把这一行:
var config = new MapperConfiguration(cfg => cfg.CreateMissingTypeMaps = true);
在创建映射器配置的地方,然后仅使用Map
方法,例如:
mapper.Map(objForDynamicMapping, mappedItem);
而不是DynamicMap
。
希望它会有所帮助。
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