我有一组数据存储在对象ReportModel中,如下所示:
public class ReportModel
{
public List<CarListingModel> CarListings {get; set;}
}
public class CarListingModel
{
public long CarId {get; set;}
public long OwnerId {get; set;}
public string CarColor {get; set;}
}
public class GroupedListingModel
{
public long OwnerId {get; set;}
public int TotalCarCount {get; set;}
public string CarColors {get; set;}
}
我已经在CarListingModel对象中选择了一组数据,如下所示:
var list = someData.Where(...).Select(l => new CarListingModel
{
CarId = l.CarId,
OwnerId = l.OwnerId,
CarColor = l.Color
});
我用来获取与每个OwnerId对应的TotalCarCount的代码如下所示:
var result = list.GroupBy(p=> p.OwnerId, p=> p.CarId, (key, g) => new GroupedListingModel {
OwnerId = key,
TotalCarCount = g.Count()
}).ToList();
但是,我想要做的是返回一个键值对,其中包含多个属性的对象中的值,例如,汽车数量和汽车颜色列表。像这样的东西(显然不起作用):
var result = list.GroupBy(p=> p.OwnerId, p=> p.CarId, p=> p.CarColor (key, g1, g2) => new GroupedListingModel
{ OwnerId = key,
TotalCarCount = g1.Count(),
CarColors = string.Join(", ", g2.ToList());
}).ToList();
我试图以不同的方式创建分组列表模型,但不确定我是否在正确的道路上:
public class GroupedListingModel_2
{
public long OwnerId {get; set;}
public DetailsModel Details {get; set;}
}
public class DetailsModel
{
public int TotalCarCount {get; set;}
public string CarColors {get; set;}
}
现在我认为这些数据会更好地构建为字典,但我再次不确定如何从“#list”列表中获取数据。达到我想要的结果。
答案 0 :(得分:2)
var result = list.GroupBy(p => p.OwnerId, (key, g) => new GroupedListingModel
{
OwnerId = key,
TotalCarCount = g.Count(),
CarColors = string.Join(", ", g.Select(x => x.CarColor).Distinct().OrderBy(x => x)),
}).ToList()
但是为了保持数据结构,你可以稍微改变你的模型:
public class GroupedListingModel
{
public long OwnerId { get; set; }
public int TotalCarCount { get; set; }
public IEnumerable<string> CarColors { get; set; }
}
GroupBy
结果选择器:
CarColors = g.Select(x => x.CarColor)