TwoCanoe's post in Input box with up\down control but using hex as the input was marked as the answer
Good catch. Nearly, not a dot but a comma.
#include <GUIConstantsEx.au3>
#include <EditConstants.au3>
Local $sMyHex = "FFFFFF"
$hGUI = GUICreate("Test", 500, 500)
$cInput = GUICtrlCreateInput($sMyHex, 10, 100, 100, 20, $ES_CENTER)
$cDummyInput = GUICtrlCreateInput(Number("0x" & $sMyHex), 110, 100, 100, 20)
$cUpDown = GUICtrlCreateUpdown($cDummyInput)
GUICtrlSetLimit($cUpDown, 16777215, 0) ; Set range for valid 6-digit hex values (0 to FFFFFF)
GUICtrlSetState($cDummyInput, $GUI_FOCUS)
GUISetState()
While 1
Switch GUIGetMsg()
Case $GUI_EVENT_CLOSE
Exit
Case $cDummyInput
; Remove the dot
Local $iDecimalValue = Number(StringReplace(GUICtrlRead($cDummyInput), ",", "")) ; CHANGED HERE
Local $sHexValue = Hex($iDecimalValue, 6) ; Convert to 6-digit hex
GUICtrlSetData($cInput, $sHexValue)
EndSwitch
WEnd
Many thanks ioa747
