Albert,

I've just tried. It's not convenient to append 0 to the end, because cursor goes automatically to the next line. Say, I type 1, then I see 1000 with cursor on another line.

I also don't like to define class in a program. I always use class designer instead. I understand, that sometimes it's only way to define class in a program, but I prefer to do it visually.


>Here is an example with an editbox. I'll leave it up to you to solve the problem of the caret (text insertion point indicator) shifting one character to the right for every line after line 1.
>
>

>oForm = createobject("TestForm")
>oForm.Visible = .t.
>read events
>
>define class TestForm as form
>  add object edtValidated as ValidatedEditbox
>  procedure QueryUnload
>    clear events
>  endproc
>enddefine
>
>define class ZipValidator as custom
>
>  DigitCount = 5
>	
>  function init
>    lparameters tnDigitCount
>		
>    if vartype( tnDigitCount ) = 'N'
>      this.DigitCount = tnDigitCount
>    endif
>  endfunc
>
>  function ValidateString
>    lparameters tcString
>		
>    local array laString[1]
>    local i, lnLineCount
>		
>    if vartype( tcString ) = 'C'
>      lnLineCount = alines(laString, tcString, .t.)
>      tcString = ""
>      for i = 1 to lnLineCount
>        if !empty(laString[i])
>          laString[i] = transform(int(val(laString[i])))
>          * padr() is used because you are formatting ZIP Codes
>          laString[i] = padr(laString[i], this.DigitCount, '0')
>          tcString = tcString + laString[i] + chr(13)
>        endif
>      endfor
>    endif
>
>    return tcString
>
>  endfunc
>
>enddefine
>
>define class ValidatedEditbox as editbox
>
>  * default validator, for some reason createobject() won't work here
>  Validator = null
>	
>  function init
>    lparameters toValidator
>		
>    * we are using deligation for the validator
>    if vartype( toValidator ) = 'O'
>      this.Validator = toValidator
>    else
>      this.Validator = createobject("ZipValidator")
>    endif
>  endfunc
>
>  procedure InteractiveChange
>    this.Value = this.Validator.ValidateString(this.Value)
>  endproc
>	
>enddefine
>