How to Disable and enable without flicker?

[Sonke Brummerloh]

In my program the main window must be disabled when a message box appears.
In this way the user have to answer the message box before he can go on in the main window.
To do this I wrote the lines 1, 2, 3 and 5 in the callback function Button_Click (see below),
but the main window was in the background after the message box was answered.
After I added line 4 the main window gets to the foreground but now there is a little flicker
because the window disappears and reappears.
And now my question: Is there a way to disable and enable the main window without a flicker?

'Here is the program:

#COMPILE EXE
#INCLUDE "Win32api.inc"
GLOBAL hDlg AS LONG
'------------------------------------------------------------------------------
CALLBACK FUNCTION Button_Click() AS LONG
1: DIALOG DISABLE hDlg
2: MSGBOX("Hallo!")
3: DIALOG ENABLE hDlg
4: DIALOG SHOW STATE hDlg, %SW_HIDE
5: DIALOG SHOW STATE hDlg, %SW_SHOWNORMAL
END FUNCTION
'------------------------------------------------------------------------------
FUNCTION PBMAIN() AS LONG
DIALOG NEW 0, "Test-Program", 0,0, 640, 480, %WS_SYSMENU OR %WS_EX_TOPMOST TO hDlg
CONTROL ADD BUTTON, hDlg, 1, "Click me!", 100,100,100,50,,CALL Button_Click
DIALOG SHOW MODAL hDlg
END FUNCTION



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[Borje Hagsten]

I think it's better to use the MessageBox API instead. Remove
all disable/enable code and try the following:

  MessageBox hDlg, "Hello", "Title", %MB_OK

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[Lance Edmonds]

Instead of using MSGBOX, use the MessageBox() API and specify the original dialog as the parent, that way you should be able to avoid all of the problems with restoring the original window.

A couple of other notes for you:
1. There is no need to use a global variable, as CBHNDL will identify the dialog in the callback function.
2. the %WS_EX_TOPMOST is an extended style, and you are using it in the normal style position.
3. You need to explicitly test for a click event before processing the callback event... there could be other notification messages sent to your callback, and as it stands, the callback will treat all messages as a clickl without any regard to the real message.
4. When processing a message in a callback, be sure to return TRUE (non-zero) so that the default handler knows not to pass the message any further (such as to the dialog callback, if one exists, or the default handler itself).

So, with these points in mind, here is my version of your program...

#COMPILE EXE
#INCLUDE "Win32api.inc"
'------------------------------------------------------------------------------
CALLBACK FUNCTION Button_Click() AS LONG
    IF CBMSG <> %WM_COMMAND AND CBCTLMSG <> %BN_CLICKED THEN EXIT FUNCTION
    MessageBox CBHNDL, "Hello World!", "Caption", %MB_OK
    FUNCTION = 1
END FUNCTION
'------------------------------------------------------------------------------
FUNCTION PBMAIN() AS LONG
    DIM hDlg AS LONG
    DIALOG NEW 0, "Test-Program", 0,0, 160, 120, %WS_SYSMENU OR %WS_CAPTION, %WS_EX_TOPMOST TO hDlg
    CONTROL ADD BUTTON, hDlg, 1, "Click me!", 30,35,100,50,,CALL Button_Click
    DIALOG SHOW MODAL hDlg
END FUNCTION

I hope this helps!


------------------
Lance
PowerBASIC Support
mailto:[email protected][email protected]</A>

[Edwin Knoppert]

Afaik, he just wants the msgbox modal..

Use %MB_TASKMODAL for that.
No hassle with disabled windows.

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[email protected]

[Gafny Jacob]

Or better

MessageBox hDlg, "Hello", "Title", %MB_OK OR %MB_TASKMODAL

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[This message has been edited by Gafny Jacob (edited October 22, 2000).]

[Lance Edmonds]

Using MessageBox() does create a modal dialog as long as you give it the parent dialog handle...


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Lance
PowerBASIC Support
mailto:[email protected][email protected]</A>

[Sonke Brummerloh]

Thank you for your help!
My problem is solved.

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[Edwin Knoppert]

Lance,

Yes modal but i believe for THAT parent window only.
But if you have multiple windows the taskmodal is better (if needed).

Now we are talking modal here what about the inputbox$.
Can't get that one modal..


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[email protected]

[Lance Edmonds]

The question specifically concerned a single application window/dialog.

InputBox$ is a bit like LINE INPUT... fine for simple tasks where a modal dialog is not required... constructing a replacement that fits your requirements is a cinch with DDT.




------------------
Lance
PowerBASIC Support
mailto:[email protected][email protected]</A>