Linq其中在条款

Question

我有层次结构，其中部门包含团队和团队包含委托。我想要做的是获得一个给定部门下的代表名单。我试图这样做：

var teams = from tms in db.Teams 
      where tms.DepartmentID == DepartmentID 
      select tms; 

var TeamDelegates = from tds in db.J_TeamDelegates 
        where tds.TeamID in teams.TeamID //error here 
        select tds; 

但团队集合不允许您引用特定的属性，就好像它是一个集合。我想说的是“在团队集合中选择TeamIDs的所有代表”。

Answer 1

var TeamDelegates = from tds in db.J_TeamDelegates 
        where teams.Any(x => x.TeamID == tds.TeamID) 
        select tds; 

Answer 2

var TeamDelegates = db.Teams 
       .Where(tms => tms.DepartmentID == DepartmentID) 
       .SelectMany(tms => db.J_TeamDelegates 
             .Where(tds => tds.TeamID == tms.TeamID)) 

Answer 3

我想你可以在这里使用一个连接。

var TeamDelegates = from tms in db.Teams 
        where tms.DepartmentID == DepartmentID 
        join tds in db.J_TeamDelegates on tms.TeamID equals tds.TeamID 
        select tds; 

Answer 4

var delegates = db.Departments 
    .Where(department => department.ID == 123) 
    .SelectMany(department => department.Teams) 
    .SelectMany(team => team.Delegates);