c# - 带有两个 where 子句的 Linq 语句

Question

我正在尝试解决以下问题。

    public class Competition
{
    public int Id { get; set; }
    public string Name { get; set; }
    public IList<ResultInfo> ResultInfos { get; set; }
    public IList<Event> ChildEvents { get; set; }
}


public class ResultInfo
{
    public int Id { get; set;}
    public string ResultInfoName { get; set;}
    public int Season { get; set; }
}

public class Event
{
    public int Id { get; set; }
    public string EventName { get; set; }
    public IList<ResultInfo> ResultInfos { get; set; } 
}

我正在尝试如下查询，以尝试从比赛和事件中获取“2013”​​赛季的结果信息。有知道的请指教。

if (year.HasValue)
{
   model = model.Where(x => x. ??           
}

Answer 1

你可以这样做:

var competitions = new Competition(); // Populated competition class

var results = (from c in competitions
               from e in c.ChildEvents
               from ri in e.ResultInfos
               where ri.Season == 2013).ToList();

不清楚为什么你需要一个额外的 where 但你可以扩展它并有另一个子句，例如

where ri.Season == 2013 && EventName == "Event"

正如@von.v 所指出的，您可以通过 Competition 类直接访问 ResultInfos，因此您可以通过以下方式简化它:

   var results = (from c in competitions
                  from ri in c.ResultInfos
                  where ri.Season == 2013).ToList();