How do I alter a global constant from an unbound txtbox on a form?

[Royston Edwards]

I have a number of global constants in a module made for that purpose. They are primarily price constant that rarely change, but also includes VAT and discount rates.

How can I alter these values from a form?


I have a form with the values showing in textboxes, but they are not editable.

Am i going about this the right way?

Thanks (again) for any help you can give.

RPE

[colintis]

Have you tried making a command button to save the new values?

As the textboxes simply read once from the global variables, then it could be re-assign with new values by executing an event such as command button's On_Click()

[Royston Edwards]

Thanks for the reply colintis:

I'd been working flat out on a complicated (for me!) database for hours when I came across this problem. I see what you mean about the cmdButton, but I also can't actually alter the value in the textbox - the same as if it were locked. I'm guessing it's something to do with the 'variables' being global and/or in a separate module, but I can find nothing on this in any of my books or online.

The 'VAT issue' (sales tax in most countries I think) must be a common one, but having already tried to put such values into a table, I figured the best way would be a constant...but how does one alter a constant...by definition I guess you don't...maybe a 'normal' variable?
Thinking while typing! Bet you got better weather outside your window than I have!!
Thanks again.
stonward.

[colintis]

Well I don't want to have good weather in this season down in Australia as its too hot here....Besides since the bloody flood passed by last month, most places are still maintaining power by renting generators, I wish I'm replying you in a swimming pool...

Back to topic, indeed a constant is not editable, sorry that I missed out this part. If possible, try search the constant variable where its created, it must be within the modules or classes. Or it can be a datatype function that generates with certain methods.

[Royston Edwards]

I hope the flood literally 'passed you by'....

I've been going about this 'constant' problem the wrong way of course...I'm gonna re-ask the question from where I am now: I've placed a public variable in a 'declarations' module, initialized it with a value and used a function to call it on my form. Works great, but still can't figure how to alter the value!
Thanks for your time thus far Colintis.

stonwardR

[NeoPa]

It's good sense to post the new question separately (found From a txtbox on a form, how can I alter an initialized variable value?). I read it but couldn't see any way it could make sense. Maybe that's because I don't make the sort of assumptions you would Royston. Maybe Colintis would fare better. I'm happy to look again though if it can be made clearer.

[ADezii]

@ALL - You can actually modify the Value of a CONSTANT Permanently from within a Form. You would Open the Code Module containing the CONSTANT Declaration, Search for the Current Value assigned to the CONSTANT, change it, Close and Save the Module, then return Focus to the Form where the Code originated.

[Lysander]

As ADezii says, this can be done in code. I do it all the time when changing assigned drives.

Obviously you would need to adapt the text below to match your own constant string, but this is the code I use.

Private Sub cmdChangeDrive_Click()
On Error GoTo cmdChangeDrive_Click_Err
Dim db As Database
Dim td As TableDef
Dim i As Integer, j As Integer, var As Variant
Dim GotPrimary As Boolean
Dim strAttach As String
Dim strNewAttach As String
Dim strNewCode As String
Dim strNewMDW As String
 
Dim mdl As Module
Dim intLine As Integer, strLine As String
 
'"c:\Education\EducationCode.mdb"
strNewCode = NewLiveCode & Right(LCode, Len(LCode) - 1)
 
'";DATABASE=c:\Education\EducationData.mdb"
strNewAttach = Left(LData, 10) & NewLiveData & Right(LIVEDATA, Len(LIVEDATA) - 11)
 
'"c:\Education\Education.mdw"
strNewMDW = NewLiveMDW & Right(LMDW, Len(LMDW) - 1)
 
        DoCmd.OpenModule "basConstants"
        ' Return reference to Module object.
        Set mdl = Modules("basConstants")
 
        For intLine = 1 To mdl.CountOfDeclarationLines
        strLine = mdl.Lines(intLine, 1)
        If InStr(strLine, "LIVECODE") > 0 Then
            mdl.ReplaceLine intLine, "Global Const LIVECODE = " & Chr(34) & strNewCode & Chr(34)
        End If
        If InStr(strLine, "LIVEDATA") > 0 Then
            mdl.ReplaceLine intLine, "Global Const LIVEDATA = " & Chr(34) & strNewAttach & Chr(34)
        End If
        If InStr(strLine, "LIVEMDW") > 0 Then
            mdl.ReplaceLine intLine, "Global Const LIVEMDW = " & Chr(34) & strNewMDW & Chr(34)
        End If
        Next
        DoCmd.Close acModule, "basConstants", acSaveYes
 
cmdChangeDrive_Click_Exit:
   Exit Sub
cmdChangeDrive_Click_Err:
   MsgBox Err.Description & " in cmdChangeDrive_Click"
   Resume cmdChangeDrive_Click_Exit
End Sub