Lab for Week 8 - Step by Step

Very Busy (VB) Mail Order

Do the housekeeping required to setup your project.

This includes:

Naming the Project
Naming the Form
Changing the Form Caption
Saving the Project

Creating a New Project Directory

Saving the Form

Saving the Project File

This is a fairly easy example that makes use of a lookup table. Here is the User Interface:

You must select a weight and a zone from the tables and click the Find Rate button to calculate the rate.

Initialize the accumulator table to hold the shipping charges for each Weight / Zone combination (multi dimensional table) in Form Load

Clear will de-select the ListBox controls and blank the charge. Print Summary will display a list of transactions and a total as described below.

The Calculate process will use the ListBox indexes to pull the rate out of the lookup table initialized in Form Load.

This is more or less a dump of the contents to the accumulator array. This accumulator array will be implemented as a UDT containing the Rate, Zone, and Cost .

The UDT and the Arrays will be declare as Public in a Module.

Build the report in Form Paint or Form Activate

Public Variables declared in a project module

Public Type ShippingCharges
    strZone As String
    strWeight As String
    sngRate As Single
End Type

Public m_udtTransaction(20) As ShippingCharges

Public m_intNumberTransactions As Integer
Public m_sngTotalCharges As Single
Public m_sngRate(0 To 4, 0 To 3) As Single

m_sngRate is a 5 by 4 table.
m_udtTransaction(20) contains 20 elements indexed 0 - 19

Build the report in From Paint

Private Sub Form_Paint()

    Dim intIndex As Integer

    Me.Cls
    Me.Print
    Me.Print
    Me.Font.Name = "Courier New"
    Me.Print
    Me.Print , "Weight", "Zone", "Price"
    Me.Print

    If m_intNumberTransactions = 0 Then
       Me.ForeColor = vbRed
       Me.Print , , "No data to summarize"
       Me.ForeColor = vbBlack
       Exit Sub
    End If

    For intIndex = 0 To m_intNumberTransactions - 1
       Me.Print , m_udtTransaction(intIndex).strWeight, _
           m_udtTransaction(intIndex).strZone, _
           FormatCurrency(m_udtTransaction(intIndex).sngRate)
    Next intIndex

    Me.Print
    Me.Print , "Total Shipping Charges: ", FormatCurrency(m_sngTotalCharges)

End Sub

Maintain the accumulators and edit the input in the Find Rate event handler

Edits
Build the Result on the Form
Update the Accumulators with the new Transaction Details
Maintain the Total Cost figure

Private Sub cmdRate_Click()
    Dim intWeightSub As Integer
    Dim intZoneSub As Integer

    intWeightSub = lstWeight.ListIndex
    intZoneSub = lstZone.ListIndex

    If intWeightSub = -1 Then
        MsgBox "Please select the weight.", vbExclamation, "Missing Data"
        Exit Sub
    End If

    If intZoneSub = -1 Then
        MsgBox "Please select the zone.", vbExclamation, "Missing Data"
        Exit Sub
    End If

    lblShipping.Caption = _
             FormatCurrency(m_sngRate(intWeightSub, intZoneSub))
    m_udtTransaction(m_intNumberTransactions).strZone = _
             lstZone.List(intZoneSub)
    m_udtTransaction(m_intNumberTransactions).strWeight = _
             lstWeight.List(intWeightSub)
    m_udtTransaction(m_intNumberTransactions).sngRate = _
             m_sngRate(intWeightsub, intZoneSub)

    m_intNumberTransactions = m_intNumberTransactions + 1
    m_sngTotalCharges = m_sngTotalCharges + _
             m_sngRate(intWeightSub, intZoneSub)

End Sub

This completes the lab

Back to Week 8