C# Linq每次出现值时，绑定到ViewModel

我需要得到一个球员列表和每个球队说，球员是相关联的，并将其添加到我的ViewModel

视图模型

public class PlayersViewModel
{
    public long PlayerID { get; set; }
    public string PlayerName { get; set; }
    public List<long> TeamID { get; set; } //Players can be assigned to 1 or more teams
}

• 球员

因此，对于上面的示例表，播放器1-John Doe在ViewModel中应该有一个由2个TeamID组成的数组。[100011002].

目标

我正在尝试创建一个包含TeamID集合的

列表

代码

public List<PlayersViewModel> GetPlayers()
{
    var playersInTeam = new PlayersInTeamsBLL();

    var pit = playersInTeam.GetPlayersInTeams();

    var playerDetail = Players;

    var list = from p in pit
        join team in Teams on p.TeamID equals team.TeamID // Only get teams that related to club
        join pd in playerDetail on p.PlayerID equals pd.PlayerID //Link a player to 
        where pd.IsArchived == false
        select new PlayersViewModel { TeamID  = team.TeamID, PlayerID = p.PlayerID, PlayerName = pd.Forename + " " + pd.Surname};

    return list.ToList();
}

public List GetPlayers（）
{
var playersInTeam=新的PlayersInTeamsBLL（）；
var pit=playersInTeam.GetPlayersInTeams（）；
var playerDetail=玩家；
var list=来自坑中的p
在p.TeamID等于team.TeamID//上加入团队，仅获取与俱乐部相关的团队
p.PlayerID等于pd.PlayerID//将玩家链接到
其中pd.IsArchived==false
选择新的PlayerViewModel{TeamID=team.TeamID，PlayerID=p.PlayerID，PlayerName=pd.Forename+“”+pd.姓氏}；
return list.ToList（）；
}

我得到了
null
PlayerIDs，显然我的团队ID没有被填充

有什么建议/解决方案吗？
试试这样的方法：

var viewModels = playerDetail.Select(p => new PlayersViewModel()
{
  PlayerID = p.PlayerID,
  PlayerName = String.Format("{0} {1}", p.ForeName, p.Surname),
  TeamID = pid.Where(pidElement => pidElement.PlayerID == p.PlayerID)
              .Select(pidElement => pidElement.TeamID).ToList()
}).ToList();

var teamsFinal = from p in pit
                 join pd in playerDetail on p.PlayerID equals pd.PlayerID 
                 where pd.IsArchived == false
                 group new {p,pd} by  new 
                                     { 
                                        pd.PlayerID ,
                                        pd.ForeName, 
                                        pd.SurName
                                     } into g
                 select new PlayersViewModel
                 {
                     TeamID = g.Select(x => x.p.TeamID).ToList(), 
                     PlayerID = g.Key.PlayerID, 
                     PlayerName = g.Key.ForeName + " " + g.Key.SurName
                 };

总的来说，在我看来，你试图从错误的角度解决这个问题。您首先需要一个玩家列表，然后是他们的团队，而不是一个玩家团队关联列表，然后是玩家详细信息，因此您应该从
playerDetail
对象开始（我假设它是所有
player
对象的
IEnumerable
）

一个旁注：考虑到你可以在你的<代码>播放器类中添加一个吸收器，它可以给你全名而不需要总是连接名字和姓氏。比如：
public string FullName
{
  get { return String.Format("{0} {1}", this.FirstName, this.Surname); }
}

您需要使用group by将其分组，如下所示：

var viewModels = playerDetail.Select(p => new PlayersViewModel()
{
  PlayerID = p.PlayerID,
  PlayerName = String.Format("{0} {1}", p.ForeName, p.Surname),
  TeamID = pid.Where(pidElement => pidElement.PlayerID == p.PlayerID)
              .Select(pidElement => pidElement.TeamID).ToList()
}).ToList();

var teamsFinal = from p in pit
                 join pd in playerDetail on p.PlayerID equals pd.PlayerID 
                 where pd.IsArchived == false
                 group new {p,pd} by  new 
                                     { 
                                        pd.PlayerID ,
                                        pd.ForeName, 
                                        pd.SurName
                                     } into g
                 select new PlayersViewModel
                 {
                     TeamID = g.Select(x => x.p.TeamID).ToList(), 
                     PlayerID = g.Key.PlayerID, 
                     PlayerName = g.Key.ForeName + " " + g.Key.SurName
                 };

你完全正确@Shaaman。只需插入您的代码，它就可以运行得很好。是的，关于球员的细节你是对的，我从错误的一端攻击它。还有，很好的建议，我也要补充一下。谢谢你的帮助！非常感谢。还有一件事，@Jezzabeanz。。。可能只是我，所以拿着这个放一撮盐。。。但我发现使用LINQ查询语法只有在必须进行连接时才有用。在大多数情况下，方法语法似乎更清晰。但正如我所写的——这可能纯粹是主观的。我完全同意，我只在进行连接时使用查询语法，我认为出于某种原因我必须这样做。干杯@Jezzabeanz供参考：）
var teamsFinal = from p in pit
                 join pd in playerDetail on p.PlayerID equals pd.PlayerID 
                 where pd.IsArchived == false
                 group new {p,pd} by  new 
                                     { 
                                        pd.PlayerID ,
                                        pd.ForeName, 
                                        pd.SurName
                                     } into g
                 select new PlayersViewModel
                 {
                     TeamID = g.Select(x => x.p.TeamID).ToList(), 
                     PlayerID = g.Key.PlayerID, 
                     PlayerName = g.Key.ForeName + " " + g.Key.SurName
                 };