Question

Here’s the DB setup of 3 tables:

Template
-----------
TemplateId (Pk Identity)
Name

Example Data:

TemplateId  Name
1           Homepage
2           Generic Landing Page


TemplateArea (Bridge table to keep track of each template type's list of areas)
----------------
TemplateAreaId (Pk Identity)
TemplateId (Fk)
AreaId (Fk)

Example Data:

    TemplateAreaId   TemplateId   AreaId
    1                1            1
    2                1            2
    3                1            3
    4                2            1
    5                2            2

So every template has 3 areas (you’re seeing a set of templateIds (e.g. 2) and related set of AreaIds (1 & 2))

Area
-----
AreaId (Pk Name)
Name

Example Data:

    AreaId  Name
    1       Top
    2       Middle
    3       Bottom

I’m trying to get a list of Areas based on a list of TemplateAreas keyed off of AreaId in my list of TemplateAreas:

so for example I should get this list of content areas for a TemplateId 2:

AreaId  Name
1       Top
2       Middle


int templateId = 2;

List<TemplateArea> templateAreas = TemplateAreas.Where(ta => ta.TemplateId == templateId).ToList();

List<Area> areas = Areas.Where()); // this is where I'm stuck, how to get the list of areas (1 & 2) relatd to templateId 2

so in other words, get a list of Template Areas then get a list of related Areas keyed off of the specific TemplateId.

I’m basically trying to join to TemplateArea from Area on TemplateArea.TemplateId = templateId or something like that if this were T-SQL, e.g. Something like:

select AreaId, Name from Area join TemplateArea on Area.AreaId = TemplateArea.AreaId where TemplateArea.TemplateId = templateId

Answer 1

Using your code approach as a guide, you can join to the templateAreas:

List<Area> areas = Area.Join(templateAreas, a => a.AreaId, t => t.AreaId, (a, t) => a);