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GBIC >> PowerBASIC >> Tutorials >> Controls >> Progress Bar

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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  • ProgressBar Control
    The progressbar control is simply a rectangle which can be filled with color to indicate progress on a task. It can be vertical or horizontal.

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

    • Source Code Example:
      This short example creates a complete application with a single progressbar. Progressbars do not receive messages, so no Callback function code is provided.

      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, "ProgressBar Test",300,300,200,200, _
                                            %WS_SysMenu, 0 To hDlg
            Control Add Progressbar, hDlg, 100,"", 50,50,100,20
            Progressbar Set Pos hdlg, 100, 80
            Control Set Color hdlg, 100, %Red, %Blue
            Dialog Show Modal hDlg
         End Function 
      

      In this example, the progress bar is 80% complete and the fg/bg colors are set to red and blue.

      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 the progressbar control in PowerBASIC. Variations on the Control Add ProgressBar 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 progressbar - change the orientation, change the colors and set the type of fill use (smooth or segmented).

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

    • hDlg
      The dialog handle to which the progressbar 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 also be included in txt$, such as "&Stop", to specify a hot key Alt-S. But since a progressbar control cannot get focus, using the hotkey will give focus to the next control in the tab order.

      The progressbar control does not display text, so the txt$ argument is usually set to "". However, any entered txt$ value can be accessed using the GET/SET TEXT statements. This provides the application with a control-specific property that can used for any purpose.

    • 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 progressbar 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.

    Usage
    The default step increment is 10 and the default range is 1-100.

    ProgressBar-Specific PowerBASIC Statements
    PowerBASIC provides several statements specific to the progressbar control. These allow getting/setting progressbar properties.

      ProgressBar Get POS get current position
      hDlg, id&, TO value&
      ProgressBar Get Range     get upper/lower values of range
      hDlg, id& TO LoValue&, HiValue&
      ProgressBar Set POS set position
      hDlg, id&, pos&
      ProgressBar Set Range set upper/lower values of range
      hDlg, id&, LoValue&, HiValue&
      ProgressBar Set Step set default increment value
      hDlg, id& TO step&
      ProgressBar Step increment position (by default value if increment& omitted)
      hDlg, id&, increment&

    See the Usage section above for information on how to use the values made available by these 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 (progressbar controls are windows).

    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.

        %pbs_smooth            - smooth, not segmented, display
        %pbs_vertical          - vertical advance
        %ws_border             - use thin line border
        %ws_ex_clientedge      - apply sunken edge border
        %ws_ex_staticedge      - apply 3D border
        %ws_ex_windowedge      - apply raised edge border
    

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

    Issues
    The Help section says %ws_border is the default style&, but it is not shown in the list of style& options.

    A default extstyle& is not specified in Help

    I'll update with more information as it becomes available.

    CONTROL Statement Syntax
    The following table lists the various Control statements (except the ADD statements). Most, but not all, can be used with the progressbar 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.