TextBox Input Filter?

[dlfallen]

Has anyone figured out a way to filter textbox input? For example, I wish to have the textbox ignore any key press that is not numeric. I tried the IsNumber function in the KeyPress event but that doesn't work.

The first approach I tried was:

Sub TextBox1_KeyPress (key)
if IsNumeric(key) = False then key = ""
End Sub

But changing the variable "key" within that subroutine does not do anything to what is displayed in the textbox. To illustrate this, replace the "if" statement above with "key = R". The textbox will still display what you type, not the value "R".

My second approach was to chop the right-hand character off of TextBox1.Text but alas, TextBox1.Text is not updated until AFTER the TextBox1.KeyPress(key) subroutine has been completed.

The only other events for a textbox are GotFocus and LostFocus, neither of which helps for this problem. The KeyPress event allows me to detect which key was pressed, but does not let me do anything about it.

Any ideas?

-dlfallen

[Erel]

You should use IgnoreKey method:
If IsNumeric(key) = false then TextBox1.IgnoreKey

[dlfallen]

Thanks Erel. Your response was quick and to the point, as usual!

-dlfallen

[Rioven]

B4PPC community, Hi!

I'm coding a dynamic textbox input and need help (the last item).
Any simple or correct solution for these filters?

Sub HHStart_KeyPress (key) 

  'input only number
If IsNumber(key) = false AND Asc(key) <> 8  Then HHstart.IgnoreKey

  'mouse selected character and replace
If StrLength(HHStart.Text) <=2 AND HHstart.SelectionLength<>0 Then
s = HHStart.SelectionStart
HHstart.Text=StrRemove(HHstart.Text,s,HHstart.SelectionLength)
HHStart.SelectionStart=s
End If

  'limiting input length
If StrLength(HHstart.text)>=2 AND Asc(key) > 31 Then HHstart.IgnoreKey

  'limiting input number range
????????? from 0 to 24 only

End Sub

Thanks in advance

[agraham]

Could be a bit more elegant, especially if you removed the need to replace a selected character, but it works.

Sub HHStart_KeyPress (key)

	'process only numbers, Asc("0")=48, AsSc("1")= 50 etc. and backspace = 8
	If (IsNumber(key) = false AND Asc(key) <> 8) Then
		HHstart.IgnoreKey
		Return
	End If

	If HHstart.SelectionLength <> 0 Then
		s = HHStart.SelectionStart
		If s = 0 AND Asc(key) > 50 AND  StrLength(HHStart.Text) >=2 Then 
			' only allow first digit to be in range
			HHstart.IgnoreKey
			Return
		End If
		HHstart.Text=StrRemove(HHstart.Text,s,HHstart.SelectionLength)
		HHStart.SelectionStart=s
	End If

             'limit input number range 
  	If StrLength(HHStart.Text) > 0 AND IsNumber(key) Then
		first = Asc(StrAt(HHStart.Text,0))
 		If first > 50 Then
			HHstart.IgnoreKey ' first digit more than "2"
		Else If	first = 50 AND Asc(Key) > 52 Then
			HHstart.IgnoreKey ' final number would be > 24
		Else If StrLength(HHStart.Text) >= 2
			HHstart.IgnoreKey ' final number would be more then two digits
		End If		
	End If
End Sub

[Rioven]

Hi agraham, thanks for your help, I could apply you techniques but still need to fix something...

when mouse is placed in between the 2 digits and use backspace, I could enter number that results more than 24, sometimes cannot enter any valid number.

or

When there is an existing 1 digit, and input number before this digit, I could enter number that results more than 24, sometimes cannot enter any valid number.

My problem looks simple, but seems no shortcut solution?

but if you can easily solve the above...will be much appreciated.

thanks again.

[Erel]

Maybe you can use a NumUpDown control instead of a TextBox?

[agraham]

Originally Posted by Erel

Maybe you can use a NumUpDown control instead of a TextBox?

Or maybe a TrackBar?

The logic is more complicated than it seems. So brute force then?

Sub HHStart_KeyPress (key)
	'process only numbers and backspace
	If (IsNumber(key) = false AND Asc(key) <> 8) Then
		HHstart.IgnoreKey
		Return
	End If
End Sub

Sub HHStart_LostFocus (key)
	'process only numbers and backspace
	If HHStart.Text <0 OR HHStart.Text > 24 Then
		Msgbox("Must be between 0 and 24")
	HHStart.Focus
	End If
End Sub

[Rioven]

Originally Posted by Erel

Maybe you can use a NumUpDown control instead of a TextBox?

Yes Erel, I have thought about that and more often applied on hours, but if I have solution for these kind of filters on textbox, I could think of some other positive applications.

Originally Posted by agraham

The logic is more complicated than it seems

difficult for years of not writing code like me, only started again when found Basic4PPC and still refreshing and learning. I could try to do some logic flowcharting then...as it seems I could not do it on the spot anymore.


thank you!

[agraham]

Originally Posted by Rioven

if I have solution for these kind of filters on textbox, I could think of some other positive applications.

I just love a challenge! Try to break this one

Sub HHStart_KeyPress (key)
	' I know this takes time but this is slow user input processing and avoids global clutter
	MAXNUM = 3456
	HHshadow = HHstart.text
	
	If (IsNumber(key) = false AND Asc(key) <> 8) Then
		'process only numbers, Asc("0")=48, AsSc("1")= 50 etc. and backspace = 8		
		HHstart.IgnoreKey
		Return
	Else If	 HHstart.SelectionLength <> 0 Then
		' part of string selected
		ss = HHStart.SelectionStart
		sl = HHStart.SelectionLength
		hl = StrLength(HHstart.text)
		first = SubString(HHshadow,0,ss)
		last = SubString(HHshadow,ss+sl,hl-sl)
		HHshadow = first & key & last		
	Else
		' no selection so process normally and check limit
		HHshadow = HHshadow & key
	End If
	
	If IsNumber(key) AND  HHshadow > MAXNUM   Then
		HHstart.IgnoreKey
		Return	
	End If
End Sub