Before the slider is created, a temporary SLDCDATA data structure is allocated, and variables are specified for the slider control window handle and slider style. The SLDCDATA data structure is allocated so that the scale increments and spacing of the slider can be specified.
The slider style variable enables the application to specify style bits, SLS_* values, that are used to customize the slider.
You create a slider by using the WC_SLIDER window class name in the ClassName parameter of WinCreateWindow call. The handle of the slider control window is returned in the slider window variable.
After the slider is created, but before it is made visible, the application can set other slider control characteristics, such as:
The settings in the preceding list are just a few that an application can specify. Slider control messages are used to specify these settings.
The sample code in the following figure shows an example of how a linear slider is created. The main components of the slider are labeled.
SLDCDATA sldcData; /* SLDCDATA data structure */CHAR szTickText[5]; /* Text strings variable */
USHORT idx; /* Counter for setting text */
/* strings */
HWND hwndSlider; /* Slider window handle */
ULONG ulSliderStyle; /* Slider styles */
/**********************************************************************/
/* Initialize the parameters in the data structure. */
/**********************************************************************/
sldcData.cbSize = sizeof(SLDCDATA); /* Size of SLDCDATA structure */
sldcData.usScale1Increments = 6; /* Number of increments */
sldcData.usScale1Spacing = 0; /* Use 0 to have slider calculate */
/* spacing */
/**********************************************************************/
/* Set the SLS_* style flags to the default values, plus slider */
/* buttons right. */
/**********************************************************************/
ulSliderStyle = SLS_HORIZONTAL | /* Slider is horizontal */
SLS_CENTER | /* Slider shaft centered in */
/* slider window */
SLS_HOMELEFT | /* Home position is left edge of */
/* slider */
SLS_PRIMARYSCALE1 | /* Scale is displayed above */
/* slider shaft */
SLS_BUTTONSRIGHT; /* Slider buttons at right end of */
/* slider */
/**********************************************************************/
/* Create the slider control window. */
/* The handle of the window is returned in hwndSlider. */
/**********************************************************************/
hwndSlider = WinCreateWindow(
hwndClient, /* Parent window handle */
WC_SLIDER, /* Slider window class name */
(PSZ)NULL, /* No window text */
ulSliderStyle, /* Slider styles variable */
(SHORT)10, /* X coordinate */
(SHORT)10, /* Y coordinate */
(SHORT)150, /* Window width */
(SHORT)80, /* Window height */
hwndClient, /* Owner window handle */
HWND_TOP, /* Sibling window handle */
ID_SLIDER, /* Slider control window ID */
&sldcData, /* Control data structure */
(PVOID)NULL); /* No presentation parameters */
/**********************************************************************/
/* Set tick marks at several places on the slider shaft using the */
/* primary scale. */
/**********************************************************************/
WinSendMsg(hwndSlider, /* Slider window handle */
SLM_SETTICKSIZE, /* Message for setting tick mark */
/* size. */
MPFROM2SHORT(
SMA_SETALLTICKS, /* Attribute for setting all tick */
/* marks to the same size */
6), /* Draw tick marks 6 pixels long */
NULL); /* Reserved value */
/**********************************************************************/
/* Set text above the tick marks. */
/**********************************************************************/
for (idx = 0; idx <= 5; idx++) /* Count from 0 to 5 */
{
itoa(10*idx, szTickText, 10); /* Set text at increments of 10 */
WinSendMsg(hwndSlider, /* Slider window handle */
SLM_SETSCALETEXT, /* Message for setting text on a */
/* slider scale */
MPFROMSHORT(idx), /* Text string counter */
MPFROMP(szTickText)); /* Text to put on slider scale */
}
/**********************************************************************/
/* Set detents between two of the tick marks on the slider shaft. */
/**********************************************************************/
WinSendMsg(hwndSlider, /* Slider window handle */
SLM_ADDDETENT, /* Message for adding detents to */
/* a slider scale */
MPFROMSHORT(5), /* Put a detent 5 pixels from home*/
NULL); /* Reserved value */
WinSendMsg(hwndSlider, /* Slider window handle */
SLM_ADDDETENT, /* Message for adding detents to */
/* slider scale */
MPFROMSHORT(25), /* Put a detent 25 pixels from */
/* home */
NULL); /* Reserved value */
/**********************************************************************/
/* Set the slider arm position to the 1st increment on the scale. */
/**********************************************************************/
WinSendMsg(hwndSlider, /* Slider window handle */
SLM_SETSLIDERINFO, /* Message for setting slider */
/* attributes */
MPFROM2SHORT(
SMA_SLIDERARMPOSITION, /* Modify slider arm position */
SMA_INCREMENTVALUE), /* Use an increment value */
MPFROMSHORT(1)); /* Value to use is 1st */
/* increment */
/**********************************************************************/
/* Since all items have been set, make the control visible. */
/**********************************************************************/
WinShowWindow(hwndSlider, /* Slider window handle */
TRUE); /* Make the window visible */