From VB to PB: The basics. But how?

[Virginio Reis]

Hi all
I'm a VB6 programmer and would like to get way of the .Net, so decided to go with PowerBasic as my next step in programming. Just bought PB and PB Forms today and I'm trying my first window. It is a very simple one: a text box and a button. All I want is when I click the button the text in the textbox changes to something I define in the code.
From the PB help, it says that when I add a control, a callback is added for that control with all the possible events (did I misundestood the help?).

That is not happening. I only get a callback for the dialogShow. Why is that? Where are the callbacks for the controllers? The code I get is following:

 
#PBFORMS CREATED V1.51
'------------------------------------------------------------------------------
' The first line in this file is a PB/Forms metastatement.
' It should ALWAYS be the first line of the file. Other
' PB/Forms metastatements are placed at the beginning and
' end of "Named Blocks" of code that should be edited
' with PBForms only. Do not manually edit or delete these
' metastatements or PB/Forms will not be able to reread
' the file correctly.  See the PB/Forms documentation for
' more information.
' Named blocks begin like this:    #PBFORMS BEGIN ...
' Named blocks end like this:      #PBFORMS END ...
' Other PB/Forms metastatements such as:
'     #PBFORMS DECLARATIONS
' are used by PB/Forms to insert additional code.
' Feel free to make changes anywhere else in the file.
'------------------------------------------------------------------------------
#COMPILE EXE
#DIM ALL
'------------------------------------------------------------------------------
'   ** Includes **
'------------------------------------------------------------------------------
#PBFORMS BEGIN INCLUDES
#IF NOT %DEF(%WINAPI)
    #INCLUDE "WIN32API.INC"
#ENDIF
#PBFORMS END INCLUDES
'------------------------------------------------------------------------------
'------------------------------------------------------------------------------
'   ** Constants **
'------------------------------------------------------------------------------
#PBFORMS BEGIN CONSTANTS
%IDD_DIALOG1  =  101
%IDC_BUTTON1  = 1001
%IDC_TEXTBOX1 = 1002
#PBFORMS END CONSTANTS
'------------------------------------------------------------------------------
'------------------------------------------------------------------------------
'   ** Declarations **
'------------------------------------------------------------------------------
DECLARE CALLBACK FUNCTION ShowDIALOG1Proc()
DECLARE FUNCTION ShowDIALOG1(BYVAL hParent AS DWORD) AS LONG
#PBFORMS DECLARATIONS
'------------------------------------------------------------------------------
'------------------------------------------------------------------------------
'   ** Main Application Entry Point **
'------------------------------------------------------------------------------
FUNCTION PBMAIN()
    ShowDIALOG1 %HWND_DESKTOP
END FUNCTION
'------------------------------------------------------------------------------
'------------------------------------------------------------------------------
'   ** CallBacks **
'------------------------------------------------------------------------------
CALLBACK FUNCTION ShowDIALOG1Proc()
    SELECT CASE AS LONG CBMSG
        CASE %WM_INITDIALOG
            ' Initialization handler
        CASE %WM_NCACTIVATE
            STATIC hWndSaveFocus AS DWORD
            IF ISFALSE CBWPARAM THEN
                ' Save control focus
                hWndSaveFocus = GetFocus()
            ELSEIF hWndSaveFocus THEN
                ' Restore control focus
                SetFocus(hWndSaveFocus)
                hWndSaveFocus = 0
            END IF
        CASE %WM_COMMAND
            ' Process control notifications
            SELECT CASE AS LONG CBCTL
                CASE %IDC_BUTTON1
                    IF CBCTLMSG = %BN_CLICKED OR CBCTLMSG = 1 THEN
                        MSGBOX "%IDC_BUTTON1=" + FORMAT$(%IDC_BUTTON1), _
                            %MB_TASKMODAL
                    END IF
                CASE %IDC_TEXTBOX1
            END SELECT
    END SELECT
END FUNCTION
'------------------------------------------------------------------------------
'------------------------------------------------------------------------------
'   ** Dialogs **
'------------------------------------------------------------------------------
FUNCTION ShowDIALOG1(BYVAL hParent AS DWORD) AS LONG
    LOCAL lRslt AS LONG
#PBFORMS BEGIN DIALOG %IDD_DIALOG1->->
    LOCAL hDlg  AS DWORD
    DIALOG NEW hParent, "Dialog1", 296, 118, 201, 121, TO hDlg
    CONTROL ADD BUTTON,  hDlg, %IDC_BUTTON1, "Button1", 105, 85, 50, 15
    CONTROL ADD TEXTBOX, hDlg, %IDC_TEXTBOX1, "TextBox1", 45, 40, 100, 13
#PBFORMS END DIALOG
    DIALOG SHOW MODAL hDlg, CALL ShowDIALOG1Proc TO lRslt
#PBFORMS BEGIN CLEANUP %IDD_DIALOG1
#PBFORMS END CLEANUP
    FUNCTION = lRslt
END FUNCTION
'------------------------------------------------------------------------------

[Adam J. Drake]

The button callback would have to be defined with the 'CONTROL ADD BUTTON' statement, but not necessary for what you want to do.

If you'll notice, when you click the button, a Message Box displays '%IDC_BUTTON1=1001'.

Remove the MSGBOX command, and use CONTROL SET TEXT to change the text in the textbox.

[Virginio Reis]

This is just a test. I want to see how the events appear. And the 'CONTROL ADD BUTTON' statement is there...

Tryed that, but didn't work (??).

[Chris Holbrook]

change the text in the button handler:

           CONTROL SET TEXT CBHNDL, %IDC_TEXTBOX1, "MY TEXT"
           'MSGBOX "%IDC_BUTTON1=" + FORMAT$(%IDC_BUTTON1), %MB_TASKMODAL

[Barry Erick]

You have the callback in there. The entire proc, not just a button callback. Look at this code:

#PBFORMS CREATED V1.51
'------------------------------------------------------------------------------
' The first line in this file is a PB/Forms metastatement.
' It should ALWAYS be the first line of the file. Other
' PB/Forms metastatements are placed at the beginning and
' end of "Named Blocks" of code that should be edited
' with PBForms only. Do not manually edit or delete these
' metastatements or PB/Forms will not be able to reread
' the file correctly.  See the PB/Forms documentation for
' more information.
' Named blocks begin like this:    #PBFORMS BEGIN ...
' Named blocks end like this:      #PBFORMS END ...
' Other PB/Forms metastatements such as:
'     #PBFORMS DECLARATIONS
' are used by PB/Forms to insert additional code.
' Feel free to make changes anywhere else in the file.
'------------------------------------------------------------------------------

#COMPILE EXE
#DIM ALL

'------------------------------------------------------------------------------
'   ** Includes **
'------------------------------------------------------------------------------
#PBFORMS BEGIN INCLUDES 
#IF NOT %DEF(%WINAPI)
    #INCLUDE "WIN32API.INC"
#ENDIF
#PBFORMS END INCLUDES
'------------------------------------------------------------------------------

'------------------------------------------------------------------------------
'   ** Constants **
'------------------------------------------------------------------------------
#PBFORMS BEGIN CONSTANTS 
%IDD_DIALOG1  =  101
%IDC_BUTTON1  = 1001
%IDC_TEXTBOX1 = 1002
#PBFORMS END CONSTANTS
'------------------------------------------------------------------------------

'------------------------------------------------------------------------------
'   ** Declarations **
'------------------------------------------------------------------------------
DECLARE CALLBACK FUNCTION ShowDIALOG1Proc()
DECLARE FUNCTION ShowDIALOG1(BYVAL hParent AS DWORD) AS LONG
#PBFORMS DECLARATIONS
'------------------------------------------------------------------------------

'------------------------------------------------------------------------------
'   ** Main Application Entry Point **
'------------------------------------------------------------------------------
FUNCTION PBMAIN()
    ShowDIALOG1 %HWND_DESKTOP
END FUNCTION
'------------------------------------------------------------------------------

'------------------------------------------------------------------------------
'   ** CallBacks **
'------------------------------------------------------------------------------
CALLBACK FUNCTION ShowDIALOG1Proc()

    SELECT CASE AS LONG CBMSG
        CASE %WM_INITDIALOG
            ' Initialization handler
             'make sure textbox is clear
             CONTROL SET TEXT CBHNDL,%IDC_TEXTBOX1,""

        CASE %WM_NCACTIVATE
            STATIC hWndSaveFocus AS DWORD
            IF ISFALSE CBWPARAM THEN
                ' Save control focus
                hWndSaveFocus = GetFocus()
            ELSEIF hWndSaveFocus THEN
                ' Restore control focus
                SetFocus(hWndSaveFocus)
                hWndSaveFocus = 0
            END IF

        CASE %WM_COMMAND
            ' Process control notifications
            SELECT CASE AS LONG CBCTL
                CASE %IDC_BUTTON1
                    IF CBCTLMSG = %BN_CLICKED OR CBCTLMSG = 1 THEN
                        CONTROL SET TEXT CBHNDL,%IDC_TEXTBOX1,"You clicked the button"
                    END IF

                CASE %IDC_TEXTBOX1

            END SELECT
    END SELECT
END FUNCTION
'------------------------------------------------------------------------------

'------------------------------------------------------------------------------
'   ** Dialogs **
'------------------------------------------------------------------------------
FUNCTION ShowDIALOG1(BYVAL hParent AS DWORD) AS LONG
    LOCAL lRslt AS LONG

#PBFORMS BEGIN DIALOG %IDD_DIALOG1->->
    LOCAL hDlg  AS DWORD

    DIALOG NEW hParent, "Dialog1", 70, 70, 201, 121, %WS_POPUP OR %WS_BORDER _
        OR %WS_DLGFRAME OR %WS_SYSMENU OR %WS_CLIPSIBLINGS OR %WS_VISIBLE OR _
        %DS_MODALFRAME OR %DS_3DLOOK OR %DS_NOFAILCREATE OR %DS_SETFONT, _
        %WS_EX_CONTROLPARENT OR %WS_EX_LEFT OR %WS_EX_LTRREADING OR _
        %WS_EX_RIGHTSCROLLBAR, TO hDlg
    CONTROL ADD BUTTON,  hDlg, %IDC_BUTTON1, "Button1", 5, 5, 50, 15
    CONTROL ADD TEXTBOX, hDlg, %IDC_TEXTBOX1, "TextBox1", 50, 50, 100, 33, _
        %WS_CHILD OR %WS_VISIBLE OR %WS_TABSTOP OR %ES_LEFT OR _
        %ES_AUTOHSCROLL OR %ES_READONLY, %WS_EX_CLIENTEDGE OR %WS_EX_LEFT OR _
        %WS_EX_LTRREADING OR %WS_EX_RIGHTSCROLLBAR
#PBFORMS END DIALOG

    DIALOG SHOW MODAL hDlg, CALL ShowDIALOG1Proc TO lRslt

#PBFORMS BEGIN CLEANUP %IDD_DIALOG1
#PBFORMS END CLEANUP

    FUNCTION = lRslt
END FUNCTION
'------------------------------------------------------------------------------

[colin glenn]

One of the confusing thing between going from VB to PB is that with VB, the IDE generates the callback automatically for you, and will even generate the callback for the various subtypes of callbacks. Under the PB model, you are in total control over what you design into the code, drawback is you don't get that wonderful instant event handler from a double click in the IDE, but able to construct callbacks where all the events you want to capture are contained within one chunk of code, or several, depending on how you want to code things.

My general preference is using the "global" dialog callback structure to handle all my events, which can make for a large main, (one of my projects has 1,300 lines of code in WinMain), but with the convenience of being able to "common" things with the Select Case functions where I got several buttons which act kin to one another with minor differences.

[Mike Stefanik]

Similar to another thread being discussed here, if you're coming from a VB background and aren't really familiar with SDK style programming, I'd recommend taking a look at Paul Squires Firefly designer. He offers a 30 day evaluation, and I suspect that you'll find the development environment to be very familiar. There are differences due to the language and syntax, of course, but overall you'll probably find it to be much easier to jump into. Drop a button control on a form, double-click on the button, you switch to a code view for the click event handler for that button. Add your code, compile, run. Pretty much the same as you would with VB. Also, as a VB programmer, if there's ActiveX controls that you want to use, Firefly makes it a fairly simple process.

My company develops networking libraries (DLLs) and ActiveX controls, and right now we offer PB examples written using our libraries with PBForms/DDT. We're going to be expanding that to also include console based examples, and we're also looking to include PB examples for our ActiveX controls. I'm going to recommend that for the ActiveX examples, we include ones written using Firefly.

There are folks here who disagree and think that you should basically stick to straight PB/DDT code and learn about Windows SDK programming. While I understand the argument, it's not something that I completely agree with. Completely switching gears from the VB quasi-objected oriented style of programming to the SDK style is non-trivial for a lot of folks. And when the bottom line is productivity and rapid development -- the emphasis there being rapid -- then a designer like Firefly can turn the frustration of learning a new language into something that is not so fearsome. In short, it lowers the "barrier to entry" for VB programmers coming to PB, and that should be considered a good thing. I suggest checking it out.

[Virginio Reis]

Very interesting discussion....

I'm looking into FireFly...

[Fred Harris]

I'm a .NET refugee too Virginio. I also have Firefly and can highly recommend it.

At...

http://www.powerbasic.com/support/pbforums/showthread.php?t=25174&highlight=SDK+Programming+Example+Series

...is my api programming example series, and the third post in that series is Form3.bas, and it shows exactly how to get to...

Private Sub cmdButton1_Click()

End Sub

...which I believe is where you are at with PowerBASIC. I just tested it and it seems to have come through the Forum transfer process OK (I posted it a year or two ago).