TdxCustomDockControl.OnCustomDrawDockingSelection Event

Enables you to custom paint docking selections.

Declaration

property OnCustomDrawDockingSelection: TdxCustomDrawSelectionEvent read; write;

Remarks

This event is deprecated, and is retained for backward compatibility only. We recommend that you do not handle this event in Windows Vista or later to avoid performance issues caused by device contexts in these operating systems.

The Sender parameter identifies the dock control being dragged.

The DC parameter specifies the handle to the display device context.

The ARect parameter specifies the potential position and size of the dock control relative to the top-left corner of the screen.

The AErasing parameter specifies whether to paint the docking selection or whether you need to erase the previously painted selection.

The Zone parameter identifies the dock zone of the target dock control that can currently accept the dragged control. This parameter can be used to determine whether the control will be docked or left floating if the dragging operation completes now. If the Zone parameter returns nil, the dock control will float if released. Otherwise, it will be docked to another control. If the Zone parameter value is not nil, you can read the target dock zone settings. This can be used, for instance, to determine the edge of the target control to which the current one will be docked if released.

Use the Handled parameter value to specify whether default painting still needs to be performed. Set this parameter to True if all painting has been done within the OnCustomDrawDockingSelection event handler.

Refer to the Docking Frame and Resizing Bar Custom Painting topic for more information and code examples.