Question

I have the following code:

        Dim dbHousing As New dcHousingDataContext
    Dim pullresidents = From p In dbHousing.webResidents _
                Select p.dorm_building, p.dorm_room, p.occupantnum _
                Order By dorm_building, dorm_room
    Dim j as integer = 1
    Dim previous As String = ""
    For Each row In pullresidents
        If previous = "" Then
            Dim wResident As New webResident
            wResident.occupantnum = j
            dbHousing.SubmitChanges()
            j = j + 1
            previous = row.dorm_building & " " & row.dorm_room
        Else
            If previous = row.dorm_building & " " & row.dorm_room Then
                Dim wResident As New webResident
                wResident.occupantnum = j
                dbHousing.SubmitChanges()
                j = j + 1
            Else
                Dim wResident As New webResident
                j = 1
                wResident.occupantnum = j
                dbHousing.SubmitChanges()
                j = j + 1
                previous = row.dorm_building & " " & row.dorm_room
            End If
        End If

    Next

When I run it, looking at the debugger everything looks okay but when I check the database table it is supposed to be inserting into – the column values (for occupantnum) haven’t changed – they are all still null!

Not sure if this is related, but note that I’ve now updated j to explicitly be an integer. I noticed while debugging that wResident.occupantnum was appearing as Type “Integer?” – but this doesn’t seem to have made any difference – when I rerun it it still says Type “Integer?”

Answer 1

You iterate over all fetched objects with For Each row In pullresidents but you never modify row. So there are no changes that could be send back to the database.