WM_VSCROLL Notification
The WM_VSCROLL message is sent to a window when a scroll event occurs in the window's standard vertical scroll bar. This message is also sent to the owner of a vertical scroll bar control when a scroll event occurs in the control.
A window receives this message through its
Syntax
WM_VSCROLL WPARAM wParam LPARAM lParam;
Parameters
- wParam
The high-order word specifies the current position of the scroll box if the low-order word is SB_THUMBPOSITION or SB_THUMBTRACK; otherwise, this word is not used.
The low-order word specifies a scroll bar value that indicates the user's scrolling request. This parameter can be one of the following values.
- SB_BOTTOM
- Scrolls to the lower right.
- SB_ENDSCROLL
- Ends scroll.
- SB_LINEDOWN
- Scrolls one line down.
- SB_LINEUP
- Scrolls one line up.
- SB_PAGEDOWN
- Scrolls one page down.
- SB_PAGEUP
- Scrolls one page up.
- SB_THUMBPOSITION
- The user has dragged the scroll box (thumb) and released the mouse button. The high-order word indicates the position of the scroll box at the end of the drag operation.
- SB_THUMBTRACK
- The user is dragging the scroll box. This message is sent repeatedly until the user releases the mouse button. The high-order word indicates the position that the scroll box has been dragged to.
- SB_TOP
- Scrolls to the upper left.
- lParam
- If the message is sent by a scroll bar, this parameter is the handle to the scroll bar control. If the message is not sent by a scroll bar, this parameter is NULL.
Return Value
If an application processes this message, it should return zero.
如果你希望你的edit组件自动滚动文本内容，就向它发送如下消息吧：
SendMessage(RzRichEdit1.Handle,WM_VScroll,SB_TOP,0);//sb_top可根据上面的值设置。