BBC BASIC Programmers' Reference

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=====Using the Date and Time Picker=====

//by Richard Russell, May 2006//\\ \\  One of the standard controls provided by the Windows API is the Date and Time Picker. This can be used when you want the user to enter a date or a time into your program. For date entry Windows can display a small clickable calendar:\\ \\ {{dtp.gif}}\\ \\  You can display the Date/Time Picker either on your main output window or in a dialogue box.\\ \\ 
==== Output window ====
\\  To display a Date/Time picker on the output window use code similar to the following:\\ \\ 
<code bb4w>
        INSTALL @lib$+"WINLIB5"
        ICC_DATE_CLASSES = &100

        DIM iccx{Size%, ICC%} : REM INITCOMMONCONTROLSEX structure
        iccx.Size% = 8
        iccx.ICC%  = ICC_DATE_CLASSES
        SYS "InitCommonControlsEx", iccx{}

        hdtp% = FN_createwindow("SysDateTimePick32", "", x%, y%, cx%, cy%, 0, style%, 0)
</code>
Here **x%,y%** is the position at which the Date/Time picker should be displayed, **cx%,cy%** is the size of the Date/Time picker window and **style%** is one of the following values (the figures in brackets are suggested window sizes for the different styles):\\ \\ 

  * 0 - to display a date picker using the short date format (cx%=88, cy%=20)
  * **4** - to display a date picker using the long date format (cx%=120, cy%=20)
  * **9** - to display a time picker (cx%=72, cy%=20)
\\  To read the currently selected date or time from the control use code similar to the following:\\ \\ 
<code bb4w>
        DIM systemtime{Year{l&,h&}, Month{l&,h&}, DayOfWeek{l&,h&}, Day{l&,h&}, \
        \              Hour{l&,h&}, Minute{l&,h&}, Second{l&,h&}, Milliseconds{l&,h&}}

        DTM_GETSYSTEMTIME = &1001
        SYS "SendMessage", hdtp%, DTM_GETSYSTEMTIME, 0, systemtime{}

        day% = systemtime.Day.l&
        month% = systemtime.Month.l&
        year% = systemtime.Year.h& * 256 + systemtime.Year.l&
        hour% = systemtime.Hour.l&
        minute% = systemtime.Minute.l&
        second% = systemtime.Second.l&
</code>
To close the control use the following code:\\ \\ 
<code bb4w>
        PROC_closewindow(hdtp%)
</code>
\\ 
==== Dialogue box ====
\\  To display a Date/Time picker in a dialogue box use code similar to the following:\\ \\ 
<code bb4w>
        INSTALL @lib$+"WINLIB2"
        ICC_DATE_CLASSES = &100
        WS_VISIBLE = &10000000
        WS_CHILD = &40000000
        WS_GROUP = &20000
        BS_DEFPUSHBUTTON = 1

        DIM iccx{Size%, ICC%} : REM INITCOMMONCONTROLSEX structure
        iccx.Size% = 8
        iccx.ICC%  = ICC_DATE_CLASSES
        SYS "InitCommonControlsEx", iccx{}

        dtpdlg% = FN_newdialog("Date/Time picker", 20, 20, 150, 140, 8, 300)

        PROC_dlgctrl(dtpdlg%, "", 101, 8, 8, 64, 14, \
        \            WS_VISIBLE + WS_CHILD + style%, "SysDateTimePick32")

        PROC_pushbutton(dtpdlg%, "OK", 1, 12, 120, 56, 14, WS_GROUP + BS_DEFPUSHBUTTON)
        PROC_pushbutton(dtpdlg%, "Cancel", 2, 80, 120, 56, 14, 0)

        PROC_showdialog(dtpdlg%)
</code>
Where **style%** has one of the values listed above. Again the size of the Date/Time picker control will need to be modified according to the style, but here the size is specified in dialogue box units rather than pixels (see the main [[http://www.bbcbasic.co.uk/bbcwin/manual/bbcwing.html#dlgitem|BBC BASIC for Windows documentation]]).\\ \\  To read the currently selected date or time from the control when the OK button is clicked use code similar to the following:\\ \\ 
<code bb4w>
        click% = 0
        ON SYS click% = @wparam% AND &FFFF : RETURN

        REPEAT
          WAIT 1
        UNTIL !dtpdlg% = 0 OR click% = 1 OR click% = 2

        ON SYS OFF

        DTM_GETSYSTEMTIME = &1001
        IF click% = 1 THEN
          DIM systemtime{Year{l&,h&}, Month{l&,h&}, DayOfWeek{l&,h&}, Day{l&,h&}, \
          \              Hour{l&,h&}, Minute{l&,h&}, Second{l&,h&}, Milliseconds{l&,h&}}

          SYS "SendDlgItemMessage", !dtpdlg%, 101, DTM_GETSYSTEMTIME, 0, systemtime{}

          day% = systemtime.Day.l&
          month% = systemtime.Month.l&
          year% = systemtime.Year.h& * 256 + systemtime.Year.l&
          hour% = systemtime.Hour.l&
          minute% = systemtime.Minute.l&
          second% = systemtime.Second.l&
        ENDIF

        PROC_closedialog(dtpdlg%)
</code>
You will want to use **ON ERROR** and **ON CLOSE** statements to ensure that "PROC_closedialog" is called even if the program is terminated unexpectedly.