The ChartStartChaning event notifies your application once the user starts resizing or moving a bar at runtime using the mouse. The ChartEndChanging event occurs once the operation ends. The ChartStartChaning event is fired in the following cases:

• Move bars
• Resizes the start of the bar.
• Resizes the end of the bar.
• Adds a new link.
• Resizes the percent value of the bar.
• Creates a new bar.
• Resizes a time scale unit in the base level area.
• Magnifies a time scale unit by double clicking the base level area.
• The user selects or unselects a date.
• The user moves the chart's vertical splitter.
• The user moves the chart's horizontal splitter ( histogram )
• An Undo/Redo operation is performed.

For instance, you can use the ChartStartChanging event to shows the grid lines while resizing, and use the ChartEndChaning to hide the grid lines. 

Use the StartBlockUndoRedo / EndBlockUndoRedo methods to collect the user operations as a block, so next time the Undo/Redo operation is performed, the entire block of operations is performed or restored at once. For instance, if you have a bar related to several other bars, and so moving a bar implies moving several other bars, each moving is recorded as a single undo/redo operation, so the operations are restored once at the time. Instead, if you use the StartBlockUndoRedo / EndBlockUndoRedo methods when your operation starts / ends, the collection of operations is recorded as a block of instructions, so the next time Undo operation is called the entire block is restored or performed at once.

---

Send comments on this topic.

© 1999-2012 Exontrol.COM, Software. All rights reserved.