A scroll event holds information about events sent from stand-alone scrollbars and sliders. Note that starting from wxWidgets 2.1, scrolled windows send the wxScrollWinEvent which does not derive from wxCommandEvent, but from wxEvent directly - don't confuse these two kinds of events and use the event table macros mentioned below only for the scrollbar-like controls.
Derived from
wxCommandEvent
wxEvent
wxObject
Include files
<wx/event.h>
Event table macros
To process a scroll event, use these event handler macros to direct input to member functions that take a wxScrollEvent argument. You can use EVT_COMMAND_SCROLL... macros with window IDs for when intercepting scroll events from controls, or EVT_SCROLL... macros without window IDs for intercepting scroll events from the receiving window -- except for this, the macros behave exactly the same.
| EVT_SCROLL(func) | Process all scroll events. |
| EVT_SCROLL_TOP(func) | Process wxEVT_SCROLL_TOP scroll-to-top events (minimum position). |
| EVT_SCROLL_BOTTOM(func) | Process wxEVT_SCROLL_BOTTOM scroll-to-bottom events (maximum position). |
| EVT_SCROLL_LINEUP(func) | Process wxEVT_SCROLL_LINEUP line up events. |
| EVT_SCROLL_LINEDOWN(func) | Process wxEVT_SCROLL_LINEDOWN line down events. |
| EVT_SCROLL_PAGEUP(func) | Process wxEVT_SCROLL_PAGEUP page up events. |
| EVT_SCROLL_PAGEDOWN(func) | Process wxEVT_SCROLL_PAGEDOWN page down events. |
| EVT_SCROLL_THUMBTRACK(func) | Process wxEVT_SCROLL_THUMBTRACK thumbtrack events (frequent events sent as the user drags the thumbtrack). |
| EVT_SCROLL_THUMBRELEASE(func) | Process wxEVT_SCROLL_THUMBRELEASE thumb release events. |
| EVT_SCROLL_CHANGED(func) | Process wxEVT_SCROLL_CHANGED end of scrolling events (MSW only). |
| EVT_COMMAND_SCROLL(id, func) | Process all scroll events. |
| EVT_COMMAND_SCROLL_TOP(id, func) | Process wxEVT_SCROLL_TOP scroll-to-top events (minimum position). |
| EVT_COMMAND_SCROLL_BOTTOM(id, func) | Process wxEVT_SCROLL_BOTTOM scroll-to-bottom events (maximum position). |
| EVT_COMMAND_SCROLL_LINEUP(id, func) | Process wxEVT_SCROLL_LINEUP line up events. |
| EVT_COMMAND_SCROLL_LINEDOWN(id, func) | Process wxEVT_SCROLL_LINEDOWN line down events. |
| EVT_COMMAND_SCROLL_PAGEUP(id, func) | Process wxEVT_SCROLL_PAGEUP page up events. |
| EVT_COMMAND_SCROLL_PAGEDOWN(id, func) | Process wxEVT_SCROLL_PAGEDOWN page down events. |
| EVT_COMMAND_SCROLL_THUMBTRACK(id, func) | Process wxEVT_SCROLL_THUMBTRACK thumbtrack events (frequent events sent as the user drags the thumbtrack). |
| EVT_COMMAND_SCROLL_THUMBRELEASE(func) | Process wxEVT_SCROLL_THUMBRELEASE thumb release events. |
| EVT_COMMAND_SCROLL_CHANGED(func) | Process wxEVT_SCROLL_CHANGED end of scrolling events (MSW only). |
The difference between EVT_SCROLL_THUMBRELEASE and EVT_SCROLL_CHANGED
The EVT_SCROLL_THUMBRELEASE event is only emitted when actually dragging the thumb using the mouse and releasing it (This EVT_SCROLL_THUMBRELEASE event is also followed by an EVT_SCROLL_CHANGED event).
The EVT_SCROLL_CHANGED event also occurs when using the keyboard to change the thumb position, and when clicking next to the thumb (In all these cases the EVT_SCROLL_THUMBRELEASE event does not happen).
In short, the EVT_SCROLL_CHANGED event is triggered when scrolling/ moving has finished independently of the way it had started. Please see the widgets sample ("Slider" page) to see the difference between EVT_SCROLL_THUMBRELEASE and EVT_SCROLL_CHANGED in action.
Remarks
Note that unless specifying a scroll control identifier, you will need to test for scrollbar orientation with wxScrollEvent::GetOrientation, since horizontal and vertical scroll events are processed using the same event handler.
See also
wxScrollBar, wxSlider, wxSpinButton,
wxScrollWinEvent, Event handling overview
Members
wxScrollEvent::wxScrollEvent
wxScrollEvent::GetOrientation
wxScrollEvent::GetPosition
wxScrollEvent(WXTYPE commandType = 0, int id = 0, int pos = 0, int orientation = 0)
Constructor.
int GetOrientation() const
Returns wxHORIZONTAL or wxVERTICAL, depending on the orientation of the scrollbar.
int GetPosition() const
Returns the position of the scrollbar.