在我的
Linq中,我试图使一个内部连接到一个可空字段.员工和部门有关系,部门可能有一个员工身份证件或可能有一个零.那么,如果我只想要满足内部连接的记录(对于null EmployeeID,没有结果),那么我的加入是什么：
var result = from emp in employees
join dept in departments
on new { Source = emp.EmployeeID }
equals new { Source = dept.EmployeeID };
我有一个例外：
The type of one of the expressions in the join clause is incorrect.
Type Inference Failed in a call to ‘join’.
谢谢
解决方法
如果你扭转你的加入并把一点点放在那里呢？
var result = from department in departments
where department.EmployeeID != null
join employee in employees
on department.EmployeeID.Value equals employee.EmployeeID
select new { employee,department };
