RadioButton WM_COMMAND

#include <GUIConstants.au3>
#include <WindowsConstants.au3>

$hWnd = GUICreate("Test", 400, 200)
$cRadio_On = GUICtrlCreateRadio("On", 15, 5, 60, 20)
$cRadio_Off = GUICtrlCreateRadio("Off", 15, 30, 60, 20)
$cInput = GUICtrlCreateInput("", 15, 60, 200, 25)
GUISetState()

Global $bInputState = 1

GUIRegisterMsg($WM_COMMAND, "_WM_COMMAND")

While True
    Switch GUIGetMsg()
        Case $GUI_EVENT_CLOSE
            Exit
    EndSwitch
WEnd

Func _WM_COMMAND($hWnd, $iMsg, $wParam, $lParam)
    Switch $wParam
        Case $cRadio_On
            If Not $bInputState Then
                GUICtrlSetState($cInput, $GUI_ENABLE)
                $bInputState = 1
            EndIf
        Case $cRadio_Off
            If $bInputState Then
                GUICtrlSetState($cInput, $GUI_DISABLE)
                $bInputState = 0
            EndIf
    EndSwitch
EndFunc