我将如何编写在网格视图中显示用户名而不是用户ID的linq查询

Question

how would I write linq query that would display user name instead of userID in a gridview.

var q = from u in entities.problems
                       join a in entities.my_aspnet_membership on u.user_id equals a.userId
                       join c in entities.my_aspnet_users on a.userId equals c.id
                       where c.id == a.userId
                       select new { u.problem_id, c.name, u.problem_description, u.problem_reported_datetime, u.problem_history}; 

What I am looking is when uasing login in the webiste only to see problems they submitted.

Answer 1

Bind only those columns needed to display the result. Turn off the AutoGeneratedColumns and add BoundField columns.

Answer 2

There are couple of issues with your query:

1. Where part ( where c.id == a.userId ) does not make sense.
2. Join with membership table - why is this needed? This join could potential give you multiple rows for one problem (if user has multiple roles) - eliminate if it's not needed.

For example,

var q = from u in entities.problems
                       join c in entities.my_aspnet_users on u.user_id equals c.id
                       select new { 
                              u.problem_id, c.name, u.problem_description, 
                              u.problem_reported_datetime, u.problem_history
                       }; 

This will give you all problems along with user name - bind the grid column with "name" column.

If you want to list the problems for only logged in user then you have to add where part such as where u.user_id = currentUserId where currentUserId variable will hold the value of logged in user.