VB 2008, SQL Server 2005 Express, Using LINQ

Dim db As New CasinoHRDataContext
Dim deptid = From d In db.Departments _
Where d.Department _
Like Me.ListBoxDepartments.SelectedItem.ToString _
Order By d.DepartmentID _
Select d.DepartmentID

'Label1.Text = deptid.Single.ToString

Dim add As New Position With {.DepartmentID = deptid, .Position = txtPosition.Text}
db.Positions.InsertOnSubmit(add)
db.SubmitChanges()
txtPosition.Text = ""
showTable()

Hi i'm trying to add a new record to table positions this has a fk from table departments. I use a query to return the departmentID based on what is selected in listboxdepartments. I've checked that the right departmentID is being returned (hence the label1.text = deptid.single.tostring).

In the add variable i'm getting the following error for deptid (Value of type 'System.Linq.IQueryable(Of Integer)' cannot be converted to 'Integer'.)

it's some kind of conversion error but i'm not sure where to go from here. All help appreciated.

regards