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GBIC >> PowerBASIC >> Tutorials >> Controls >> Frame Control

PowerBASIC Information Center Tutorials
These tutorials were written to help you get a quick, but thorough, understanding of PowerBASIC - the scope of the language as well as it's specific capabilities.

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  • Frame Control
    The frame control is simply a box with text in the upper edge. It is often used to enclose controls within a group (such as option controls) but does not act as a parent of child controls. It only provides a visual grouping of controls.

    The label font/color can be changed but the bounding line and body color are not under programmatic control.

    • Syntax:
      Control Add Frame, hDlg, id&, txt$, x, y, xx, yy, _
                                          style&, extsytle& CALL callback
      

    • Source Code Example:
      This short example creates a complete application with a single frame. This tutorial page discusses most of the statements used, however the DDT, Controls, Messages, and Callback tutorials provide background information that may be helpful in understanding the example.

         #Compile Exe
         Global hDlg As Dword
         Function PBMain() As Long
            Dialog New Pixels, 0, "Frame Test",300,300,200,200, _
                                            %WS_SysMenu, 0 To hDlg
            Control Add Frame, hdlg, 100, "Frame Example", 20,20,150,90, %BS_Left
            Dialog Show Modal hDlg
         End Function
      

      An additional example of a callback function is provided further down this page.

    • Visual Examples:
      And here are a few examples of what you can do with frames in PowerBASIC. Variations on the Control Add Frame statement were used to create the examples. In some cases, other Control statements were used to modify the results.

      As you can see, there's really not much you can do with a button - change the font, change the justification of the text, and multi-line content is about it.

    Arguments
    The Control Add statement is used to create all new controls. Here are the statement's arguments and any special significance to the frame control.

    • hDlg
      The dialog handle to which the frame control is to be added. The value was returned by the DIALOG NEW statement.

    • id&
      The id& argument is a control identifier assigned by the programmer. It must be a value of 1-65535. Values of 100+ are suggested, as PowerBASIC pre-assigns identifiers with special meaning. Numeric equates are suggested over the use of literal values.

    • txt$
      An ampersand can be included in txt$, such as "&Stop", to specify a hot key Alt-S. But since a frame control cannot get focus, using the hotkey will give focus to the next control in the tab order. In WinXP, the hotkey underline will not appear until the Alt key is pressed.

    • x,y and xx,yy
      The integer x,y and xx,yy dimensions use the same units as the parent dialog. (x,y) is the upper/left coordinates of the control. (xx,yy) is the width/height of the control.

    • style& and extstyle&
      The style& and extstyle& arguments (listed below) are optional. If not supplied, default values are used (see the table below). If values are supplied, they completely replace default values (i.e., the entered values are not in addition to the default values).

    • CALL
      The "CALL callback" section is optional. If not supplied, the callback function of the parent dialog is used. An example callback function for frame controls is provided further down this page. The #MESSAGE COMMAND compiler directive can be used to prevent sending %WS_NOTIFY messages to the callback function. By default, both %WS_NOTIFY and %WS_COMMAND messages are sent.

    Frame transparency is not a built-in feature.

    Usage Notes
    Some of these comments refer to the ComboBox-specific statement in the next section below.

    The PowerBASIC frame is not a parent control (as it is in some implementations). If you want the appearance of child controls in the frame, draw the frame first and the "child" controls last.

    Changing line color/thickness and frame body color are not supported by PowerBASIC.

    Frame-Specific PowerBASIC Statements
    Although PowerBASIC provides control-specific statements for some controls (Treeview, Imagelist, ...), there are no FRAME PowerBASIC statements.

    Messages, Notifications, Styles, and ExtSstyles
    There are four types of named constants in the following table. All are pulled from the MSDN web site.

    • Notifications - event notifications a control receives
    • Messages - controls may send these
    • Styles - affect the visual look of a control
    • ExtStyles - additional values that affect the visual look

    The first column contains control-specific named constants and the second column contains generic window named constants (frames are windows).

    Since the PowerBASIC frame control is derived from the Windows button class, the first column contains MSDN button control constants.

    Also, if the PowerBASIC Help file has an entry on the value, it is highlighted in yellow. If the value was noted in PowerBASIC Help as a default value, it is also shown in bold text.

    In the values for notifications, descriptions starting with -n and -c refer to events received through the %wm_notify and %wm_command messages. By default, PowerBASIC controls can receive both of these messages.

       

    And here is a short description of many of the named constants corresponding to notifications, styles, and extstyle - particularly those discussed in the PowerBASIC Help topics.

        bcn_dropdown          -n click on drop down arrow on control
        bcn_hotitemchange     -n mouse enters/leaves client area
        bn_clicked            -c mouse click
        bn_dblclk             -c mouse doubleclick
        bn_disable            -c (n/a - win3.0 only)
        bn_doubleclicked      -n mouse doubleclick
        bn_hilite             -c (n/a - win3.0 only)
        bn_killfocus          -c focus is lost
        bn_paint              -c control should be painted
        bn_pushed             -c (n/a - win3.0 only)
        bn_setfocus           -n focus is received
        bn_unhilite           -c when highlight should be removed 
        bn_unpushed           -c (n/a - win3.0 only)
        bs_bottom             - text at bottom
        bs_center             - center text horizontally
        bs_default            - heavy black border, ENTER selects, 1 per dialog
        bs_defpushbutton      - same as bs_default
        bs_left               - text on left side
        bs_multiline          - wrap text
        bs_notify             - allows bn_killfocus/bn_setfocus messages
        bs_pushlike           - toggle between raised/sunken
        bs_right              - text on right side
        bs_top                - text at top
        bs_vcenter            - center text vertically
        nm_customdraw         -n custom draw operation
        wm_ctlcolorbtn        - before drawing owner-drawn control
        ws_border             - use thin line border
        ws_disabled           - initially disabled (no user input)
        ws_ex_left            - generic left-aligned properties
        ws_ex_right           - generic right-aligned properties
        ws_ex_transparent     - draw controls/windows beneath control first
        ws_group              - starts/ends group. use ws_tabstop style.
        ws_tabstop            - allows receipt of keyboard focus
    

    Callback Function
    A frame control does not send messages and does require/support a callback function.

    CONTROL Statement Syntax
    The following table lists the various Control statements (except the ADD statements). Most, but not all, can be used with the frame control. A one-line description of the statement and then its syntax are presented.

      CONTROL DISABLEdisable
      hDlg, id&
      CONTROL ENABLEenable hDlg, id&
      CONTROL GET CHECKcheck state hDlg, id& TO iResult1&
      CONTROL GET CLIENTtop/left location hDlg, id& TO wide&, high&
      CONTROL GET LOCtop/left location hDlg, id& TO x&, y&
      CONTROL GET SIZEwidth/height hDlg, id& TO width&, height&
      CONTROL GET TEXTtext hDlg, id& TO txt$
      CONTROL GET USERget user data hDlg, id&, index& TO retvar&
      CONTROL HANDLE window handle for control id hDlg, id& TO hCtl&
      CONTROL KILLremove control hDlg, id&
      CONTROL POSTput message in queue (non-blocking) hDlg, id&, Msg&, wParam&, lParam&
      CONTROL REDRAWschedule redraw of control hDlg, id&
      CONTROL SENDsend message to control, wait for processing hDlg, id&, Msg&, wParam&, lParam& TO iResult2&
      CONTROL SET CHECKset check for 3state or checkbox hDlg, id&, checkstate&
      CONTROL SET CLIENTchange size to specific client area size hDlg, id&, wide&, high&
      CONTROL SET COLORset fg/bg color hDlg, id&, fgcolor&, bgcolor&
      CONTROL SET FOCUSset focus hDlg, id&
      CONTROL SET FONTselect font for a control hDlg, id&, fonthandle&
      CONTROL SET LOCrelocate control within dialog hDlg, id&, x&, y&
      CONTROL SET OPTIONset check state of option control hDlg, id&, minid&, maxid&
      CONTROL SET SIZEchange control size hDlg, id&, width&, height&
      CONTROL SET TEXTchange control text hDlg, id&, text$
      CONTROL SET USERset user data hDlg, id&, index&, uservalue&
      CONTROL SHOW STATE     toggle visibility hDlg, id&, showstate& TO iResult3&

    If you have any suggestions or corrections, please let me know.