Question

I have the following in my db table:

- MailingId | GroupName | ServiceId
-   1       |  group1   |   3
-   2       |  group1   |   5
-   3       |  group1   |   8
-   4       |  group2   |   null
-   5       |  group3   |   null
...

In my view i have 2 groups of checkboxes:

• 1) (services) with id’s 3,5,8 (serviceId).
• 2) and a list of checkboxes for mailing groups (group1, group2, group3)

I need to select the following using LINQ:

Select rows that I have selected in ServiceId checkbox list PLUS any other. For example if I check off ServiceId’s (3 and 5) and group “Group3” then my output would be rows MailingId: 1, 3 and 5. HOWEVER, if I select ANY service from (first group of checkboxes) AND DO NOT select “Group1” from mailing group checkboxes then rows with Group1 SHOULD NOT be in the output.

I’m using EF4. Please help.
Thanks

Answer 1

The 2 arrays would be the selections that are posted from your view

int[] selectedservices = {3,5};
string[] selectedgroups = {"group3"};

using (Model model = new Model())
{
    bool b = selectedservices.Contains(1);

            var mailinglists = from m in model.MalingSet
                               where selectedgroups.Contains(m.GroupName)
                               && ((m.ServiceId.HasValue && selectedservices.Contains(m.ServiceId.Value)) || m.ServiceId.HasValue == false)
                               select m.MailingId;
}