What does this visual basic code do????(line by line..)

**vb5prgrmr** · Oct 21 '09, 06:12 AM

Code:

'declare variables to be used and in this case these variables represent DAO (Data Access Object) objects although so you can understand more the order has been changed by me to more represent the heirarchy of the objects
Dim WS As Workspace
Dim db As Database
Dim rs As Recordset

Dim Max As Long


'this even is called after initialize
Private Sub Form_Load()

'create the workspace via the dbengine (jet) object
Set WS = DBEngine.Workspaces(0)

'this example you have shown is an example of bad programming practice as none of these variables are declared. To remedy this place Option Explicit at top of code window prior to any declarations
DbFile = (App.Path & "\Database\AddressBook.mdb")
PwdString = "swordfish"

'open the database
Set db = DBEngine.OpenDatabase(DbFile, False, False, ";PWD=" & PwdString)

'open a recordset, namely the addresses table
Set rs = db.OpenRecordset("Addresses", dbOpenTable)

'retrieve the number of records and display
Max = rs.RecordCount
lblTotalContacts.Caption = Max

'check to see if there are any records
If rs.RecordCount = 0 Then

  'no records so exit this sub
  Exit Sub
Else

  'have records so position the recordset cursor to the first record
  rs.MoveFirst
  
  'clear list1
  List1.Clear

  'now run through rs and add the information to list1
  For i = 1 To Max
    List1.AddItem rs!FullName
    rs.MoveNext
  Next i
  List1.ListIndex = 0
End If

'call a sub that enables/disables buttons depending upon...?
ButtonsEnabled
End Sub

'this event is called when the mouse moves over the form
Private Sub Form_MouseMove(Button As Integer, Shift As Integer, X As Single, Y As Single)
'call sub...
ButtonsEnabled
End Sub

Private Sub Form_Unload(Cancel As Integer)

'another example of bad programming practice with vb6 as this does not allow you to properly close your object that you have opened and may lead to memory leaks and system instability
End
End Sub

'when user clicks on an item in list1 this event is called
Private Sub List1_Click()

'the following lines are not needed as the workspace is already created and the database is already opened...
'Set WS = DBEngine.Workspaces(0)
'DbFile = (App.Path & "\Database\AddressBook.mdb")
'PwdString = "swordfish"
'Set db = DBEngine.OpenDatabase(DbFile, False, False, ";PWD=" & PwdString)

'open a recordset based upon user selection
Set rs = db.OpenRecordset("Select * from Addresses where FullName = '" & Trim(List1.List(List1.ListIndex)) & "'")

'tell compiler that we will attempt to handle any errors after this label below
On Error GoTo ErrorHandler

'another example of bad programming practice as these should be rs.fields("fieldname") for complete readability and for easier maintence by the noobie
lblName.Caption = rs("FullName")
lblNationality.Caption = rs("Nationality")
lblCountry.Caption = rs("Country")
lblBirthday.Caption = rs("Birthday")
lblCountry.Caption = rs("Country")
lblCity.Caption = rs("City")
lblAddress.Caption = rs("Address")
lblPhoneNumber.Caption = rs("PhoneNumber")
lblMobile.Caption = rs("Mobile")
lblFax.Caption = rs("Fax")
lblEMAIL.Caption = rs("E-Mail")
lblWebSite.Caption = rs("WebSite")
lblCompany.Caption = rs("Company")
Text1.Text = rs("LittleComment")

'label for the error handler. Also, missing the exit sub statement before this line
ErrorHandler:

'basically we are telling the compiler that we are trying to ignore any errors and to go to the next line and if that is so then we could have used the On Error Resume Next statement instead of telling the system that we will try to handle the error
Resume Next
End Sub

Hope that helps

Good Luck