無效表達術語「選擇」，「基團」等

Question

在我一起工作的應用程序I recevie 18個錯誤等：

Error 2 Invalid expression term 'select'  
Error 6 Syntax error, ',' expected 

似乎它被連接在一起。

我應該在哪裏尋找問題的根源？

類的所有這些錯誤的部分：

if (this.TicketType == "Delivery") 
{ 
    this.Drivers = new ObservableCollection<User>(this.loginService.GetAllDrivers()); 
} 
else if (this.TicketType == "Drivers") 
{ 
    IEnumerable<User> tickets = 
      from t in this.Tickets      // here error 
      where !string.IsNullOrEmpty(t.DriverName) 
      group t by t.DriverName into group   // here error 
      select new User() 
      { 
       Name = group.Key,      // here error 
       Id = (
        from g in group      // here error 
        select g.DriverId).First<int>() 
      }; 
    if (tickets == null) 
    { 
     this.Drivers.Clear(); 
    } 
    else 
    { 
     this.Drivers = new ObservableCollection<User>(tickets); 
    } 
    this.OnPropertyChanged("Drivers"); 
} 

Answer 1

您需要添加using System.Linq;