Using a Case statement with an Int entry from a table

Question

What is the best way to compare an Int entry from a table in a case statement?

Using SQL server 2008 R2, Visual Basic Express with LINQ to SQL.

The code I tried doesnt work:

Private Sub UpdateSetOpt()

    Dim db = New ACEDataContext
    Dim SRM = From q In db.Settings
              Where q.SettingID = frmMain.CurrentSID
              Select q.RollMethod

    Select Case SRM
        Case 1
            rbStandard.Checked = True
        Case 2
            rbProfession.Checked = True
        Case 3
            rbSpecies.Checked = True
        Case 4
            rbRandom.Checked = True
        Case Else
            rbStandard.Checked = False
            rbProfession.Checked = False
            rbSpecies.Checked = False
            rbRandom.Checked = False
    End Select

End Sub

Answer 1

SRM isn't an Integer since your From query returns a collection of items. To get just the first, use Single() :

Dim SRM = (From q In db.Settings
           Where q.SettingID = frmMain.CurrentSID
           Select q.RollMethod).Single()

If the query actually returns more than a single value the above code will fail; you need to use First instead of Single then. Both will fail if no value is returned by the query. In that case, FirstOrDefault may be used instead (but probably isn't appropriate in your situation).

Adding to that, your Select Case is a sign of code smell. You should rather create an array of all the check boxes and use the integer to map into it:

Dim checks As CheckBox() = New CheckBox() { _
    rbStandard, rbProfession, rbSpecies, rbRandom }

' Unset all checkboxes:
For Each check In checks
    check.Checked = False
End For

If SRM > 0 AndAlso SRM <= checks.Length Then
    checks(SRM - 1).Checked = True
End If

Answer 2

SRM in your case is not an int but IEnumerabe<int> .

You want the first element:

SELECT CASE SRM.FirstOrDefault():