How to allow null values for DevExpress Gridview

Question

I use the Linq for getting data from database to Gridview. So, There are many Null Cells in my database but DevExpress Gridview does not display the null values.I upload 2 photos If you look at these understand easily what i want.

My Database

DevExpress Gridview

it is my Linq Query for getting data from database.

var sorgu = from görevler in db.tbl_TaskOfProjects
                    join projeler in db.tbl_Projects
                    on görevler.project_id equals projeler.project_id
                    select new
                    {
                        görevler.p_task_id,
                        görevler.p_task_name,
                        görevler.p_task_start_date,
                        görevler.p_task_end_date,
                        görevler.p_task_status,
                        görevler.p_task_detail,
                        görevler.p_task_corporation,
                        projeler.project_id,
                        projeler.project_name
                    };
        gridGörevler.DataSource = sorgu;

Answer 1

The problem is not in GridView, but in you query. You're performing INNER JOIN between tables görevler and projeler on column project_id, which is null. You have to make LEFT JOIN.

var sorgu = from görevler in db.tbl_TaskOfProjects
                join projeler in db.tbl_Projects
                on görevler.project_id equals projeler.project_id into groupProject // <-- changed from here down
                from project in groupProject.DefaultIfEmpty()
                select new
                {
                    görevler.p_task_id,
                    görevler.p_task_name,
                    görevler.p_task_start_date,
                    görevler.p_task_end_date,
                    görevler.p_task_status,
                    görevler.p_task_detail,
                    görevler.p_task_corporation,
                    project.project_id,
                    project.project_name
                };