REFERENCE GUIDE

WM_ GETTEXTLENGTHcontent of the control. For lixt boxes, the text is the currently selected item.For button controls, the text is the button name. For other windows, thetext is the window caption.Parameters wParam Is not used.CommentsIParamIs not used.The return value is the length of the given text.WM HSCROLLThis message is sent when the user clicks the horizontal scroll bar.Parameters wParam Contains a scroll-bar code that specifies the user's scrollingrequest. It can be anyone of the following values:CommentsIParamValueSB _BOTTOMSB_ENDSCROLLSB _LINEDOWNSB_LINEUPSB_PAGEDOWNSB_PAGEUPSB_THUMBPOSITIONSB _ THUMBTRACKSB _TOPMeaningScroll to lower right.End scroll.Scroll one line down.Scroll one line up.Scroll one page down.Scroll one page up.Scroll to absolute position. Thecurrent position is provided in thelow-order word of IParam.Drag thumb to specified position. Thecurrent position is provided in thelow-order word of IParam.Scroll to upper left.Specifies the window handle of the control. If the message issent by a scroll-bar control, the high-order word of the IParamparameter contains the window handle of the control. If themessage is sent as a result of the user clicking a pop-upwindow's scroll bar, the high-order word is not used.The SB_THUMBTRACK message typically is used by applications thatgive some feedback while the thumb is being dragged.If an application scrolls the document in the window, it must also resetthe position of the thumb by using the SetScrollPos function.Chapter 6, Messages directory 655