关于 ThenMapper 的一点疑问：ThenMapper 中使用 Queryable 会一直请求数据库服务吗？

[idea-zone]

我使用下面的代码在获取 用户后，关联用户的角色：

 SysUserRoleService service = new SysUserRoleService();
            service.Context.ThenMapper(list, t =>
            {
                t.RoleIds = service.Queryable().Where(ur => ur.UserId == t.Id).Select(t => t.RoleId).ToArray();
            });

执行后，查看 Log 发现 SQL 日志如下：（下面 SELECT "roleid" FROM "userrole" WHERE ( "userid" = X) 是请求了多次数据库吗? ）

[23-07-21 17:11:36]>>【db0 SQL语句】SELECT id,loginname,loginpassword,realname,idnumber,telephone,lifestarttime,lifeendtime,idedit,state,nikename,sharefolder,blongcity,mac,deptid FROM public.user 

[23-07-21 17:11:36]>>【db0 SQL语句】SELECT "roleid" FROM "userrole"  WHERE ( "userid" = 2 ) 

[23-07-21 17:11:36]>>【db0 SQL语句】SELECT "roleid" FROM "userrole"  WHERE ( "userid" = 3 ) 

[23-07-21 17:11:36]>>【db0 SQL语句】SELECT "roleid" FROM "userrole"  WHERE ( "userid" = 4 ) 

[23-07-21 17:11:36]>>【db0 SQL语句】SELECT "roleid" FROM "userrole"  WHERE ( "userid" = 5 ) 

[23-07-21 17:11:36]>>【db0 SQL语句】SELECT "roleid" FROM "userrole"  WHERE ( "userid" = 1 ) 

[23-07-21 17:11:36]>>【db0 SQL语句】SELECT "roleid" FROM "userrole"  WHERE ( "userid" = 6 ) 

[23-07-21 17:11:36]>>【db0 SQL语句】SELECT "roleid" FROM "userrole"  WHERE ( "userid" = 7 ) 

[23-07-21 17:11:36]>>【db0 SQL语句】SELECT "roleid" FROM "userrole"  WHERE ( "userid" = 8 ) 

[23-07-21 17:11:36]>>【db0 SQL语句】SELECT "roleid" FROM "userrole"  WHERE ( "userid" = 9 ) 

[23-07-21 17:11:36]>>【db0 SQL语句】SELECT "roleid" FROM "userrole"  WHERE ( "userid" = 10 ) 

[23-07-21 17:11:36]>>【db0 SQL语句】SELECT "roleid" FROM "userrole"  WHERE ( "userid" = 11 ) 

[DotNetNext]

你用法错误要用SetContext

[DotNetNext]

SetContext 是关键 db.Queryable().SetContext(x => x.ParentId, () => item.Id, item).ToList()