square65

What exactly is $GUI_CHECKED

7 posts in this topic

#1 ·  Posted (edited)

It's not covered anywhere in the wiki.

I can see from its context that it has to do with a checkbox being checked. But in code examples it's usage baffles me.

Return BitAND(GUICtrlRead($idControlID), $GUI_CHECKED) = $GUI_CHECKED

Really doesn't make any sense to me.

Here's the example I'm looking at:

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


Example()


Func Example()
    ; Create a GUI with various controls.
    Local $hGUI = GUICreate("Example", 300, 200)


    ; Create a checkbox control.
    Local $idCheckbox = GUICtrlCreateCheckbox("Standard Checkbox", 10, 10, 185, 25)
    Local $idClose = GUICtrlCreateButton("Close", 210, 170, 85, 25)


    ; Display the GUI.
    GUISetState(@SW_SHOW, $hGUI)


    ; Loop until the user exits.
    While 1
        ;guigetmsg polls the gui to see if any events have occurred
Switch GUIGetMsg()
            Case $GUI_EVENT_CLOSE, $idClose
                ExitLoop


            Case $idCheckbox
                If _IsChecked($idCheckbox) Then
                    MsgBox($MB_SYSTEMMODAL, "", "The checkbox is checked.", 0, $hGUI)
                Else
                    MsgBox($MB_SYSTEMMODAL, "", "The checkbox is not checked.", 0, $hGUI)
                EndIf


        EndSwitch
    WEnd


    ; Delete the previous GUI and all controls.
    GUIDelete($hGUI)
EndFunc   ;==>Example


Func _IsChecked($idControlID)
    ;bitand is just an 'and'
;guictrlread reads the state or data of a control
Return BitAND(GUICtrlRead($idControlID), $GUI_CHECKED) = $GUI_CHECKED
 EndFunc   ;==>_IsChecked

 

I'm able to replace that BitAND with:

Return GUICtrlRead($idControlID)

 

And as far as I can tell, the example works exactly the same.

Edited by square65

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square65,

$GUI_CHECKED is a constant in the GUIConstantsEx.au3 file which indicated the "checked" state of a checkbox or radio - and of course there is an equivalent $GUI_UNCHECKED. ;)

You can see from the Help file that GUICtrlRead actually returns the control state for checkboxes and radios - unless the advanced parameter is set. As far as I know, this rather confusing behaviour has been part of AutoIt since it began so just accept it. Anyway, looking at the table on the GUICtrlSetState page of the Help file you can see that there are many possible states and several of them can be applied at the same time - so it is quite possible that a checkbox could be, for example, both checked and disabled. in this case, the return from GUICtrlRead would not be a simple $GUI_CHECKED, but would actually be BitOr($GUI_CHECKED, $GUI_DISABLE) and a simple check for $GUI_CHECKED would fail. So you should use BitAnd to check whether the returned value contains the value you wish - although in many cases a simple comparison is valid as there will be only the one state returned. :)

That brings us on to the subject of binary maths and using bits as flags - I suggest reading the early paragraphs of the Setting Styles tutorial in the Wiki which explains in some detail why you need to use the Bit* functions to combine and read styles - and states. ;)

I hope that helps - please ask again if not. :)

M23

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ArrayMultiColSort ---- Sort arrays on multiple columns
ChooseFileFolder ---- Single and multiple selections from specified path treeview listing
Date_Time_Convert -- Easily convert date/time formats, including the language used
ExtMsgBox --------- A highly customisable replacement for MsgBox
GUIExtender -------- Extend and retract multiple sections within a GUI
GUIFrame ---------- Subdivide GUIs into many adjustable frames
GUIListViewEx ------- Insert, delete, move, drag, sort, edit and colour ListView items
GUITreeViewEx ------ Check/clear parent and child checkboxes in a TreeView
Marquee ----------- Scrolling tickertape GUIs
NoFocusLines ------- Remove the dotted focus lines from buttons, sliders, radios and checkboxes
Notify ------------- Small notifications on the edge of the display
Scrollbars ----------Automatically sized scrollbars with a single command
StringSize ---------- Automatically size controls to fit text
Toast -------------- Small GUIs which pop out of the notification area

 

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Yep. It was nothing like what I was guessing and that helped a lot. Especially to get me a deeper understanding of the intricacies of the language. Thanks :)

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square65,

Glad I could help and that you understood. :)

Never be afraid to ask questions like this. I am sure that there are lot of other members who are very glad that you decided to ask this one - the answer to which is not as simple as it looks at first sight. ;)

M23

1 person likes this

Any of my own code posted anywhere on the forum is available for use by others without any restriction of any kind._______My UDFs:

Spoiler

ArrayMultiColSort ---- Sort arrays on multiple columns
ChooseFileFolder ---- Single and multiple selections from specified path treeview listing
Date_Time_Convert -- Easily convert date/time formats, including the language used
ExtMsgBox --------- A highly customisable replacement for MsgBox
GUIExtender -------- Extend and retract multiple sections within a GUI
GUIFrame ---------- Subdivide GUIs into many adjustable frames
GUIListViewEx ------- Insert, delete, move, drag, sort, edit and colour ListView items
GUITreeViewEx ------ Check/clear parent and child checkboxes in a TreeView
Marquee ----------- Scrolling tickertape GUIs
NoFocusLines ------- Remove the dotted focus lines from buttons, sliders, radios and checkboxes
Notify ------------- Small notifications on the edge of the display
Scrollbars ----------Automatically sized scrollbars with a single command
StringSize ---------- Automatically size controls to fit text
Toast -------------- Small GUIs which pop out of the notification area

 

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As always GREAT explanation Melba23, I was looking for this Intel :)


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You can see from the Help file that GUICtrlRead actually returns the control state for checkboxes and radios - unless the advanced parameter is set. As far as I know, this rather confusing behaviour has been part of AutoIt since it began so just accept it. Anyway, looking at the table on the GUICtrlSetState page of the Help file you can see that there are many possible states and several of them can be applied at the same time - so it is quite possible that a checkbox could be, for example, both checked and disabled. in this case, the return from GUICtrlRead would not be a simple $GUI_CHECKED, but would actually be BitOr($GUI_CHECKED, $GUI_DISABLE) and a simple check for $GUI_CHECKED would fail. So you should use BitAnd to check whether the returned value contains the value you wish - although in many cases a simple comparison is valid as there will be only the one state returned. :)

Actually,I don't  think this is true. If you use GUICtrlRead on a checkbox, the only 2 returns you'll get are 1 and 4. 1 being equal to $GUI_CHECKED and 4 being equal to $GUI_UNCHECKED.  I am not sure why it says what it says in the help file, but that has never returned the state of the checkbox or a radio control. You can try it yourself and see what I'm talking about.


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#7 ·  Posted (edited)

BrewManNH,

After testing it looks as though you are right - not that I doubted you. ;)

A change in the Help file text for GUICtrlRead seems indicated. :)

M23

Edit: And done. :)

Edited by Melba23

Any of my own code posted anywhere on the forum is available for use by others without any restriction of any kind._______My UDFs:

Spoiler

ArrayMultiColSort ---- Sort arrays on multiple columns
ChooseFileFolder ---- Single and multiple selections from specified path treeview listing
Date_Time_Convert -- Easily convert date/time formats, including the language used
ExtMsgBox --------- A highly customisable replacement for MsgBox
GUIExtender -------- Extend and retract multiple sections within a GUI
GUIFrame ---------- Subdivide GUIs into many adjustable frames
GUIListViewEx ------- Insert, delete, move, drag, sort, edit and colour ListView items
GUITreeViewEx ------ Check/clear parent and child checkboxes in a TreeView
Marquee ----------- Scrolling tickertape GUIs
NoFocusLines ------- Remove the dotted focus lines from buttons, sliders, radios and checkboxes
Notify ------------- Small notifications on the edge of the display
Scrollbars ----------Automatically sized scrollbars with a single command
StringSize ---------- Automatically size controls to fit text
Toast -------------- Small GUIs which pop out of the notification area

 

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