Question

I have two tables in my database, Building and Town. They look like this:

Building:

buildingid
buildingname

Town:

id
userid
buildingid

In Town there is one entry for each building a user has.

What i want is to populate a GridView for a user with a given userid. This GridView should include the buildingname and the number of buildings.
Building. I have tried this:

var buildings = (from Town in dc.Towns
                         join Building in dc.Buildings
                             on Town.buildingid equals Building.buildingid
                         select Building.buildingname);
        gvBuildings.DataSource = buildings;
        gvBuildings.DataBind();

But I don’t know how to get the numbers for each building.

---

I have now been working on this for a while and a couple of your answers work. I have used this code:

var buildings = dc.Towns
            .Where(t => t.userid == userid)
            .GroupJoin(dc.Buildings,
                       t => t.buildingid,
                       b => b.buildingid,
                       (Town, Buildings) => new
                                                {
                                                    BuildningName = Buildings.First().buildingname,
                                                    Count = Buildings.Count()
                                                });
        gvBuildings.DataSource = buildings.ToList();
        gvBuildings.DataBind();

When i run this code my GridView ends up looking like this:

I need the buildings to be shown in groups, grouped by the buildingname. I have tried all of the suggestions but i cant get it to work.

Answer 1

Try grouping:

var buildings = dc.Towns
                  .Where(t => t.UserId == userId)
                  .GroupJoin(dc.Buildings,
                             t => t.BuildingId,
                             b => b.BuildingId,
                             (town, buildings) => new
                             {
                                 BuildingName = buildings.First().BuildingName,
                                 Count = buildings.Count
                             });

Keep in mind that when binding to a control you must supply a collection of type (or implementing) IList. This can be accomplished by calling ToList() on the buildings collection:

gvBuildings.DataSource = buildings.ToList();
gvBuildings.DataBind();