此上下文中仅支持基元类型或枚举类型-linq联接

Question

我在尝试加入时遇到此错误

var users = _users.Get();
var userApprovals =
(from approval in _entities.ApprovalEntities
join userDetail in users on approval.UserKey equals userDetail.UserId
 where approval.EmployeeUid == employeeUid
 select new UserApproval
{
Id = approval.Id,
EmployeeUid = approval.EmployeeUid,
UserKey = approval.UserKey,
UserId = approval.UserId,
UserName = userDetail.FirstName + " " + userDetail.LastName
}).ToList();

错误此上下文中仅支持基元类型或枚举类型

感谢

Answer 1

固定，var userApprovals=

(from approval in _entities.ApprovalEntities.ToList()
join userDetail in users on approval.UserKey equals userDetail.UserId
 where approval.EmployeeUid == employeeUid
 select new UserApproval
{
Id = approval.Id,
EmployeeUid = approval.EmployeeUid,
UserKey = approval.UserKey,
UserId = approval.UserId,
UserName = userDetail.FirstName + " " + userDetail.LastName
}).ToList();

Answer 2

在我的例子中，我的问题是在不使用toList（）语句的情况下使用IEnumerable。

看，这段代码显示"error在此上下文中仅支持基元类型或枚举类型"错误：

var query = db.TemplatesDocs.Where(x => x.Id_Template == idTmpl)
        .Join(Utils.DocumentTypes, x => x.Id_Type, y => y.Id, (x, y) => new { tmpDoc = x, type = y } )
        .ToList();

看，这个代码修复了错误：

var query = db.TemplatesDocs.Where(x => x.Id_Template == idTmpl).ToList()
        .Join(Utils.DocumentTypes, x => x.Id_Type, y => y.Id, (x, y) => new { tmpDoc = x, type = y } )
        .ToList();