VB 2010 Counter from reading a file

[danielmarshall]

I am trying to make a loadcounter so that as a form loads an ID number is input into a readonly text box. This would be calculated from the hash address of the last saved record saved on the file plus 1000. I am stumped as to what to do. Any help?

[kareninstructor]

Hello,

I would suggest showing code you currently have, otherwise it's a pot-shot in which direction to go in for assisting you.

[danielmarshall]

'Zero the loadcounter
Loadcounter = 0

'Open the file to count customer data
FileOpen(1, "CustomerDetails.dat", OpenMode.Random, , , Len(Customer))
While Not EOF(1)
FileGet(1, "CustomerDetails.dat")
Loadcounter = Loadcounter + 1
End While
FileClose(1)

'add 1 to create new customer ID number
txtCustomerID.Text = (1000 + Loadcounter + 1)

[kareninstructor]

Okay, I am not versed in VB6 style of coding so if I was going to work with a hashtable it would be something like the following which may not work for you.

Adapted from MSDN BinaryFormatter class example.

Sub Serialize()
    Dim ht As New Hashtable

    For x As Int32 = 1 To 1000
        ht.Add(x, "Item" & x.ToString)
    Next

    Dim fs As New FileStream("DataFile.dat", FileMode.Create)
    Dim formatter As New BinaryFormatter
    Try
        formatter.Serialize(fs, ht)
    Catch e As SerializationException
        Console.WriteLine("Failed to serialize. Reason: " & e.Message)
        Throw
    Finally
        fs.Close()
    End Try
End Sub
Sub Deserialize()
    Dim ht As Hashtable = Nothing
    Dim fs As New FileStream("DataFile.dat", FileMode.Open)
    Try
        Dim formatter As New BinaryFormatter
        ht = DirectCast(formatter.Deserialize(fs), Hashtable)
    Catch e As SerializationException
        Console.WriteLine("Failed to deserialize. Reason: " & e.Message)
        Throw
    Finally
        fs.Close()
    End Try

    '
    ' Uncomment to see the data
    '
    'For Each de As DictionaryEntry In ht
    '    Console.WriteLine("{0}: {1}.", de.Key, de.Value)
    'Next

    TextBox1.Text = CStr((From T In ht.Cast(Of DictionaryEntry)() Select CInt(T.Key)).FirstOrDefault + 1)
End Sub