Managing Multiple GUIs

Introduction

Having several GUIs on the screen at the same time is fairly common but structuring your code to deal with this can seem quite daunting. However, as I hope this tutorial will demonstrate, it is nowhere near as difficult as it first appears.

MessageLoop Mode

Let us start with MessageLoop mode as this is where most new coders run into difficulties with multiple GUIs. This example script illustrates the problem - it exits when the [X] is clicked on either GUI:

#include <GUIConstantsEx.au3>
#include <MsgBoxConstants.au3>

Global $g_idButton3

gui1()

Func gui1()
	Local $hGUI1 = GUICreate("GUI 1", 200, 200, 100, 100)
	Local $idButton1 = GUICtrlCreateButton("Msgbox 1", 10, 10, 80, 30)
	Local $idButton2 = GUICtrlCreateButton("Show GUI 2", 10, 60, 80, 30)
	GUISetState(@SW_SHOW, $hGUI1)

	While 1
		Switch GUIGetMsg()
			Case $GUI_EVENT_NONE
				ContinueLoop
			Case $GUI_EVENT_CLOSE
				ExitLoop
			Case $idButton1
				MsgBox($MB_OK, "MsgBox 1", "Test from GUI 1")
			Case $idButton2
				GUICtrlSetState($idButton2, $GUI_DISABLE)
				gui2()
			Case $g_idButton3
				MsgBox($MB_OK, "MsgBox 2", "Test from GUI 2")
		EndSwitch
	WEnd
EndFunc   ;==>gui1

Func gui2()
	Local $hGUI2 = GUICreate("GUI 2", 200, 200, 350, 350)
	$g_idButton3 = GUICtrlCreateButton("MsgBox 2", 10, 10, 80, 30)
	GUISetState(@SW_SHOW, $hGUI2)
EndFunc   ;==>gui2

The script exits because it has a single GUIGetMsg loop and the $GUI_EVENT_CLOSE message is received when either [X] is clicked - we have no way of telling the messages from the two GUIs apart.

The simplest solution is to disable the first GUI while the second is displayed:

#include <GUIConstantsEx.au3>
#include <MsgBoxConstants.au3>

gui1()

Func gui1()
	Local $hGUI1 = GUICreate("GUI 1", 200, 200, 100, 100)
	Local $idButton1 = GUICtrlCreateButton("Msgbox 1", 10, 10, 80, 30)
	Local $idButton2 = GUICtrlCreateButton("Show GUI 2", 10, 60, 80, 30)
	GUISetState()

	While 1
		Switch GUIGetMsg()
			Case $GUI_EVENT_NONE
				ContinueLoop
			Case $GUI_EVENT_CLOSE
				ExitLoop
			Case $idButton1
				MsgBox($MB_OK, "MsgBox 1", "Test from GUI 1")
			Case $idButton2
				; Disable the first GUI
				GUISetState(@SW_DISABLE, $hGUI1)
				gui2()
				; Re-enable the first GUI
				GUISetState(@SW_ENABLE, $hGUI1)
		EndSwitch
	WEnd
EndFunc   ;==>gui1

Func gui2()
	Local $hGUI2 = GUICreate("GUI 2", 200, 200, 350, 350)
	Local $idButton3 = GUICtrlCreateButton("MsgBox 2", 10, 10, 80, 30)
	GUISetState()

	While 1
		; We can only get messages from the second GUI
		Switch GUIGetMsg()
			Case $GUI_EVENT_NONE
				ContinueLoop
			Case $GUI_EVENT_CLOSE
				GUIDelete($hGUI2)
				ExitLoop
			Case $idButton3
				MsgBox($MB_OK, "MsgBox 2", "Test from GUI 2")
		EndSwitch
	WEnd

EndFunc   ;==>gui2

This may well be all you need, but it does mean that we cannot action any of the controls on the first GUI until we close the second. And importantly we remain blocked in the While...WEnd loop within the gui2 function - go and read the Interrupting a running function tutorial to see why this is less than ideal.

So how can we deal with multiple GUIs visible at the same time? Fortunately AutoIt offers us a simple way to differentiate between GUIs in MessageLoop mode. Normally we use code like this in our idle loop to detect the messages sent by our GUI and its controls:

Switch GUIGetMsg()
	Case $GUI_EVENT_NONE
		ContinueLoop
	Case $GUI_EVENT_CLOSE
		; Code
	Case $idButton1
		; Code
EndSwitch

But when dealing with multiple GUIs, we need to use the "advanced" parameter when we call GUIGetMsg. As explained in the Help file, the function then returns an array instead of a single value. This array includes information on what exactly triggered the message, just what we need to distinguish the message that was sent (element[0] of the array) and which GUI sent it (element[1]). We can then amend our simple Switch statement above to read like this:

$aMsg = GUIGetMsg(1) ; Use advanced parameter to get an array returned
If Not IsHWnd($aMsg[1]) Then ContinueLoop ; preventing subsequent lines from processing when nothing happens

Switch $aMsg[1] ; First check which GUI sent the message
	Case $hGUI1
		Switch $aMsg[0] ; Now check for the messages sent from $hGUI1
			Case $GUI_EVENT_NONE ; it will not be necessary as we already check: If Not IsHWnd($aMsg[1]) Then
				ContinueLoop
			Case $GUI_EVENT_CLOSE
				; Code
			Case $hControl
				; Code
		EndSwitch
	Case $hGUI2
		Switch $aMsg[0] ; Now check for the messages sent from $hGUI2
			Case $GUI_EVENT_NONE ; it will not be necessary as we already check: If Not IsHWnd($aMsg[1]) Then
				ContinueLoop
			Case $GUI_EVENT_CLOSE
				; Code
			Case $idButton3
				; Code
		EndSwitch
EndSwitch

Although this looks complicated, if you take a moment to study it and you will quickly realise it is simply two Switch structures within an outer Switch. You have already dealt with a single Switch structure for a single GUI. All you are doing here is determining which Switch structure you want to use, and that depends on the GUI which sent the message which is why we need the outer Switch structure as a wrapper.

So here is an example of how to manage two GUIs simultaneously using the "advanced" parameter with GUIGetMsg:

#include <GUIConstantsEx.au3>
#include <MsgBoxConstants.au3>

Global $g_hGUI1, $g_idButton1, $g_idButton2, $g_hGUI2, $g_idButton3

example()

Func example()
	gui1()
	Local $aMsg

	While 1
		$aMsg = GUIGetMsg(1) ; Use advanced parameter to get array
		If Not IsHWnd($aMsg[1]) Then ContinueLoop ; preventing subsequent lines from processing when nothing happens

		Switch $aMsg[1] ; check which GUI sent the message
			Case $g_hGUI1
				Switch $aMsg[0] ; Now check for the messages for $g_hGUI1
					Case $GUI_EVENT_CLOSE ; If we get the CLOSE message from this GUI: $g_hGUI1 ...
						ExitLoop ;  ... exit the loop and thus exit the program
					Case $g_idButton1
						MsgBox($MB_OK, "MsgBox 1", "Test from GUI 1")
					Case $g_idButton2
						GUICtrlSetState($g_idButton2, $GUI_DISABLE)
						gui2()
				EndSwitch
			Case $g_hGUI2
				Switch $aMsg[0] ; Now check for the messages for $g_hGUI2
					Case $GUI_EVENT_CLOSE ; If we get the CLOSE message from this GUI : $g_hGUI2 ...
						GUIDelete($g_hGUI2) ; ... just delete the GUI ...
						GUICtrlSetState($g_idButton2, $GUI_ENABLE) ; ... enable button (previously disabled)
					Case $g_idButton3
						MsgBox($MB_OK, "MsgBox", "Test from GUI 2")
				EndSwitch
		EndSwitch
	WEnd

EndFunc   ;==>example

Func gui1()
	$g_hGUI1 = GUICreate("GUI 1", 200, 200, 100, 100)
	$g_idButton1 = GUICtrlCreateButton("Msgbox 1", 10, 10, 80, 30)
	$g_idButton2 = GUICtrlCreateButton("Show GUI 2", 10, 60, 80, 30)
	GUISetState()
EndFunc   ;==>gui1

Func gui2()
	$g_hGUI2 = GUICreate("GUI 2", 200, 200, 350, 350)
	$g_idButton3 = GUICtrlCreateButton("MsgBox 2", 10, 10, 80, 30)
	GUISetState()
EndFunc   ;==>gui2

As you can see, we have a single While...WEnd loop which distinguishes between the two GUIs, both GUIs and their controls remain active and we stay in the main idle loop while we wait (you did read that other tutorial I hope!).

OnEvent Mode

Coders using OnEvent mode do not usually find the same problem with multiple GUIs as they can code separate functions for each $GUI_EVENT_CLOSE as shown here:

#include <GUIConstantsEx.au3>
#include <MsgBoxConstants.au3>

Opt("GUIOnEventMode", 1)

Global $g_hGUI2, $g_idButton2

gui1()

Func gui1()
	Local $hGUI1 = GUICreate("GUI 1", 200, 200, 100, 100)
	GUISetOnEvent($GUI_EVENT_CLOSE, "On_Close_Main") ; Run this function when the main GUI [X] is clicked
	Local $idButton1 = GUICtrlCreateButton("Msgbox 1", 10, 10, 80, 30)
	GUICtrlSetOnEvent($idButton1, "On_Button1")
	$g_idButton2 = GUICtrlCreateButton("Show GUI 2", 10, 60, 80, 30)
	GUICtrlSetOnEvent(-1, "On_Button2")
	GUISetState(@SW_SHOW, $hGUI1)

	While 1
		Sleep(10)
	WEnd
EndFunc   ;==>gui1

Func gui2()
	$g_hGUI2 = GUICreate("GUI 2", 200, 200, 350, 350)
	GUISetOnEvent($GUI_EVENT_CLOSE, "On_Close_Secondary") ; Run this function when the secondary GUI [X] is clicked
	Local $idButton3 = GUICtrlCreateButton("MsgBox 2", 10, 10, 80, 30)
	GUICtrlSetOnEvent($idButton3, "On_Button3")
	GUISetState(@SW_SHOW, $g_hGUI2)
EndFunc   ;==>gui2

Func On_Close_Main()
	Exit
EndFunc   ;==>On_Close_Main

Func On_Close_Secondary()
	GUIDelete($g_hGUI2)
	GUICtrlSetState($g_idButton2, $GUI_ENABLE)
EndFunc   ;==>On_Close_Secondary

Func On_Button1()
	MsgBox($MB_OK, "MsgBox 1", "Test from GUI 1")
EndFunc   ;==>On_Button1

Func On_Button2()
	GUICtrlSetState($g_idButton2, $GUI_DISABLE)
	gui2()
EndFunc   ;==>On_Button2

Func On_Button3()
	MsgBox($MB_OK, "MsgBox 2", "Test from GUI 2")
EndFunc   ;==>On_Button3

But did you realise that you can also use what some people think of as a hybrid mode - using common OnEvent functions and then determining the specific GUI or control which called the function within the function? As an added bonus, this approach may, depending on the circumstances, let you send parameters to the functions you call - something that you normally cannot do in OnEvent mode.

#include <GUIConstantsEx.au3>
#include <MsgBoxConstants.au3>

Opt("GUIOnEventMode", 1)

Global $g_hGUI1, $g_hGUI2, $g_idButton1, $g_idButton2, $g_idButton3

gui1()

Func gui1()
	$g_hGUI1 = GUICreate("GUI 1", 200, 200, 100, 100)
	GUISetOnEvent($GUI_EVENT_CLOSE, "On_Close") ; Call a common GUI close function
	$g_idButton1 = GUICtrlCreateButton("Msgbox 1", 10, 10, 80, 30)
	GUICtrlSetOnEvent(-1, "On_Button") ; Call a common button function
	$g_idButton2 = GUICtrlCreateButton("Show GUI 2", 10, 60, 80, 30)
	GUICtrlSetOnEvent(-1, "On_Button") ; Call a common button function
	GUISetState()

	While 1
		Sleep(10)
	WEnd
EndFunc   ;==>gui1

Func gui2()
	$g_hGUI2 = GUICreate("GUI 2", 200, 200, 350, 350)
	GUISetOnEvent($GUI_EVENT_CLOSE, "On_Close") ; Call a common GUI close function
	$g_idButton3 = GUICtrlCreateButton("MsgBox 2", 10, 10, 80, 30)
	GUICtrlSetOnEvent(-1, "On_Button") ; Call a common button function
	GUISetState()
EndFunc   ;==>gui2

Func On_Close()
	Switch @GUI_WinHandle ; See which GUI sent the CLOSE message
		Case $g_hGUI1
			Exit ; If it was this GUI - we exit <<<<<<<<<<<<<<<
		Case $g_hGUI2
			GUIDelete($g_hGUI2) ; If it was this GUI - we just delete the GUI <<<<<<<<<<<<<<<
			GUICtrlSetState($g_idButton2, $GUI_ENABLE)
	EndSwitch
EndFunc   ;==>On_Close

Func On_Button()
	Switch @GUI_CtrlId ; See which button sent the message
		Case $g_idButton1
			MessageBox(1) ; We can call a function with parameters here <<<<<<<<<<<<<<<<<<<
		Case $g_idButton2
			GUICtrlSetState($g_idButton2, $GUI_DISABLE)
			gui2()
		Case $g_idButton3
			MessageBox(2) ; We can call a function with parameters here <<<<<<<<<<<<<<<<<<<
	EndSwitch
EndFunc   ;==>On_Button

Func MessageBox($iIndex)
	MsgBox($MB_OK, "MsgBox " & $iIndex, "Test from Gui " & $iIndex)
EndFunc   ;==>MessageBox

Summary

So you see that managing multiple GUIS is not as difficult as you might think. One of these methods is bound to suit your script, but do not try and mix them - only one method per script please!