C# 如何在linq中实现两个连接

C# 如何在linq中实现两个连接,c#,sql,linq,C#,Sql,Linq,我正在尝试将sql查询写入linq: 查询: select s.s_name, sub.state, sub.to, sub.evaluation, sub.task_id from submit_task sub join student s on s.id=sub.student_id join task t on t.id=sub.task_id where t.t_name = "bbbb"; var subTask = (from sub in ado.submit_task

我正在尝试将sql查询写入linq:

查询:

select s.s_name, sub.state, sub.to, sub.evaluation, sub.task_id
from submit_task sub
join student s on s.id=sub.student_id
join task t on t.id=sub.task_id
where t.t_name = "bbbb";
var subTask = (from sub in ado.submit_task
               join s in ado.student on sub.student_id equals s.id
               join t in ado.task on sub.task_id equals t.id
               where t.t_name == listView3.SelectedItems[0].Text
               select new { s.s_name, sub.state, sub.to, 
                            sub.evaluation, sub.task_id });
Linq:

select s.s_name, sub.state, sub.to, sub.evaluation, sub.task_id
from submit_task sub
join student s on s.id=sub.student_id
join task t on t.id=sub.task_id
where t.t_name = "bbbb";
var subTask = (from sub in ado.submit_task
               join s in ado.student on sub.student_id equals s.id
               join t in ado.task on sub.task_id equals t.id
               where t.t_name == listView3.SelectedItems[0].Text
               select new { s.s_name, sub.state, sub.to, 
                            sub.evaluation, sub.task_id });
但这不起作用。当我尝试dubugg时,什么都没有发生,没有错误或结果。你看到什么错误了吗

谢谢

var text = listView3.SelectedItems[0].Text;

var subTask = (from sub in ado.submit_task
  join s in ado.student on sub.student_id equals s.id
  join t in ado.task on sub.task_id equals t.id
  where t.t_name == text
  select new { s.s_name, sub.state, sub.to, sub.evaluation, sub.task_id });