c# - 左连接 linq to sql

Question

我有这个问题:

public IEnumerable<TimesheetModel> GetTicketsInProgressByUserId(int id)
{
    var query = (from workLogList in DataContext.tblWorkLogs
                 join tickets in DataContext.tblTickets on workLogList.TicketId equals tickets.TicketId
                 join project in DataContext.tblProjects on tickets.ProjectId equals project.ProjectId
                 join states  in DataContext.tblWorkflowStates on tickets.Status equals states.StateId
                 where workLogList.AccountId == id
                 group workLogList by workLogList.WorkDate into data
                 select new TimesheetModel
                 {
                     TaskDate = data.Key,
                     TimesheetList = data.Select(x => new TimesheetListModel()
                     {
                         ProjectId = x.tblTicket.tblProject.ProjectId,
                         ProjectName = x.tblTicket.tblProject.Name,
                         TaskDate = x.WorkDate,
                         TimeWorked = x.TimeWorked,
                         Note = x.Note,
                         Task = TaskString(x.tblTicket.TicketId, x.tblTicket.Title, x.TaskTitle)
                     }
                     ).ToList()
                 });
    return query.ToList();
}

在这一行中我需要使用左连接，因为我还需要使用 worklogList.TicketId == null 获取数据

join tickets in DataContext.tblTickets on workLogList.TicketId equals tickets.TicketId

如何在这种情况下使用左连接？

Answer 1

如果您只是在模型中进行关联，那么请记住将基数设置为 0..1 - *。

那么你应该可以使用点语法而不是在 linq 语句中加入。

稍后添加:

以下是我希望您在建立这些关联后结束时使用的示例(当然未经测试):

(from workLogList in DataContext.tblWorkLogs
             //join tickets in DataContext.tblTickets on workLogList.TicketId equals tickets.TicketId
             //join project in DataContext.tblProjects on tickets.ProjectId equals project.ProjectId
             //join states  in DataContext.tblWorkflowStates on tickets.Status equals states.StateId
             where workLogList.AccountId == id
             group workLogList by workLogList.WorkDate into data
             select new TimesheetModel
             {
                 TaskDate = data.Key,
                 TimesheetList = data.Select(x => new TimesheetListModel()
                 {
                     ProjectId = x.tblTicket.tblProject.ProjectId,
                     ProjectName = x.tblTicket.tblProject.Name,
                     TaskDate = x.WorkDate,
                     TimeWorked = x.TimeWorked,
                     Note = x.Note,
                     Task = TaskString(x.tblTicket.TicketId, x.tblTicket.Title, x.TaskTitle)
                 }
                 ).ToList()
             });