How to limit input length in Access form textbox?

[Killer42]

Hi all.

Does a textbox on an Access form have an equivalent of the VB6 .MaxLength property? I need to limit the length of an input string. It's not bound to anything, just used in code, but I'd prefer to limit it in the control rather than validating afterward.

[NeoPa]

Specifically no.
But you might want to check out the 'InputMask Property'. It may be able to give the required functionality.

[Killer42]

Specifically no.
But you might want to check out the 'InputMask Property'. It may be able to give the required functionality.

Nuts! I was hoping to avoid that.

Thanks, anyway.

[MMcCarthy]

Hi all.

Does a textbox on an Access form have an equivalent of the VB6 .MaxLength property? I need to limit the length of an input string. It's not bound to anything, just used in code, but I'd prefer to limit it in the control rather than validating afterward.

In code you could

 Dim someStr As String 
 
  someStr = InputBox("Enter some string: ")
  If Len(someStr) > 100 Then
	 someStr = Left(someStr,100)
	 'Msg to user
  End If

[MMcCarthy]

In code you could

 Dim someStr As String 
 
someStr = InputBox("Enter some string: ")
If Len(someStr) > 100 Then
	 someStr = Left(someStr,100)
	 'Msg to user
End If

Or if textbox, damn I should read these things better ...

 Dim someStr As String 
 
someStr = Me.textbox
If Len(someStr) > 100 Then
	 someStr = Left(someStr,100)
	 Me.textbox = someStr
	 'Msg to user
End If

[MMcCarthy]

Or if textbox, damn I should read these things better ...

 Dim someStr As String 
 
someStr = Me.textbox
If Len(someStr) > 100 Then
	 someStr = Left(someStr,100)
	 Me.textbox = someStr
	 'Msg to user
End If

I'm now wondering if you could get the realtime text value of the input and validate on KeyPress event. Preformance ???

[Killer42]

I'm now wondering if you could get the realtime text value of the input and validate on KeyPress event. Preformance ???

It's ok, I can handle the validation alright. I just didn't want to have to, because .MaxLength is ever so much simpler.

Maybe I need to use the VB6 library ;)

[MMcCarthy]

It's ok, I can handle the validation alright. I just didn't want to have to, because .MaxLength is ever so much simpler.

Maybe I need to use the VB6 library ;)

Worth a try as it should be on the list. Never tried it for something like this though.

Mary

[Killer42]

Worth a try as it should be on the list. Never tried it for something like this though.

Hm... nah!

I've just spent a few minutes browsing the References list and don't really like what I saw. Think I'll just bite the bullet and put in some code to do validation (or real-time feedback) on the form.

[MMcCarthy]

Hm... nah!

I've just spent a few minutes browsing the References list and don't really like what I saw. Think I'll just bite the bullet and put in some code to do validation (or real-time feedback) on the form.

Yeah!

It is a bit of a minefield.

When you get some time :)

Have a look on msdn regarding 'Automation' from Access.

Mary

[Killer42]

Yeah!
It is a bit of a minefield.
When you get some time :)
Have a look on msdn regarding 'Automation' from Access.

Will do.

In the meantime, I ended up going with something very simple. I just turn the field background red as long as the value is not within the required length. Although it doesn't account for the possibility of a black (zero) background, here's the routine I used.

Private Sub tx_Change()
  Static HeldColour As Long
  With tx
    If Len(.Text) > 8 Then
      If HeldColour = 0 Then
        Beep
        HeldColour = .BackColor
        .BackColor = vbRed
      End If
    Else
      If HeldColour <> 0 Then
        .BackColor = HeldColour
        HeldColour = 0
      End If
    End If
  End With
End Sub

[MMcCarthy]

If you wanted even more control:

 if Len(tx.Text) > 8 then 
Me.someothercontrol.SetFocus
Me.tx = Left(Me.tx, 8)
Msgbox("You are limited to 8 characters ....", vbOKOnly + vbWarning)
Me.tx.SetFocus
Else
>
>
>

[Killer42]

If you wanted even more control: ...

Yeah, I thought about chopping it off, but decided against it. The users know the limits, if they choose to ignore the warning then so be it.

One technique I've used in similar cases at times is to have a timer on the form. To highlight a field I do one of two things:

• set a value in the .Tag property (VB6, not sure about Access) and the timer watches for these flags and flashes the controls on and off.
• Highlight the control (typically by setting background colour), and also flag it in .Tag or whatever. The timer gradually fades the colour back to normal. This one looks quite good, actually. You get a beep, the field turns (typically) bright red, then over a few seconds it fades back to normal, but it doesn't interfere with your typing or anything.

(Note, in cases such as these the warning message might be displayed in a particular place on the form, rather than as a message box).

Damnit, I've got to stop spending so much time here - I keep getting carried away. :(

[MMcCarthy]

Never thought about using the control tags in this way. Sounds interesting.

Mary

[Killer42]

Never thought about using the control tags in this way. Sounds interesting.

I find them quite useful for this kind of thing.

One caveat, though.

I recommend that one always assume there may be other info in there. I try to

• Add my flag onto the end and make it distinctive, with something like "/FLASHFIELD", and
• Remove it without disturbing any other contents.

That way, you can make use of multiple routines that use the .Tag property, without any cross-interference.