Visual Basic

Public Function GetPlatformList() As List(Of String)

    Dim result As New List(Of String)
    Dim dbCon As New OleDb.OleDbConnection(dbConnectionString)

    Dim dbCMD As OleDb.OleDbCommand
    Dim dbReader As OleDb.OleDbDataReader

    dbCMD = New OleDb.OleDbCommand("SELECT PlatformName FROM Platforms", dbCon)

    Try
        dbCon.Open()

        dbReader = dbCMD.ExecuteReader()
        Dim HasResult As Boolean = True
        Do Until Not HasResult
            Do While dbReader.Read()
                result.Add(dbReader.GetString(0))
            Loop
            HasResult = dbReader.NextResult()
        Loop

    Catch ex As Exception
        'Error Trying
        MsgBox("Error Accessing Database: " & ex.Message, MsgBoxStyle.Critical, "Database Error")
    End Try

    dbReader.Close()
    dbCon.Close()

    'Return the list of platforms
    Return result
End Function

Variable 'dbReader' is used before it has been assigned a value. A null reference exception could result at runtime.