[Overview][Constants][Types][Classes][Procedures and functions][Index] | Reference for unit 'ComCtrls' (#lcl)

# TCustomTreeView.OnCustomDrawArrow

Event handler signalled to custom draw expand / collapse (fold) indicators for a tree node.

## Declaration

Source position: comctrls.pp line 3677

`protected property TCustomTreeView.OnCustomDrawArrow : TTVCustomDrawArrowEvent read FOnCustomDrawArrow write FOnCustomDrawArrow;`

## Description

OnCustomDrawArrow is a TTVCustomDrawArrowEvent property with the event handler signalled to custom-draw the expand/collapse (fold) indicator for a node on the tree view control.

Arguments to the event handler include:

Sender
  The tree view control for the event notification.
ARect
  TRect instance with the bounds on the drawing area where the indicator should be drawn.
ACollapsed
  Boolean value which indicates which indicator (expanded or collapsed) to to draw on the tree view control. True indicates that the collapsed arrow should be drawn.

Use the Canvas for the control to perform drawing operations in the handler routine.

OnCustomDrawArrow is signalled (when assigned) from the DoPaintNode method. If OnCustomDrawArrow has not been assigned, the default drawing routines in the class are used to paint the indicator using the style in the ExpandSignType, ExpandSignSize, ExpandSignWidth, and ExpandSignColor properties.

## See also

TCustomTreeView.DoPaintNode |  | Renders the specified tree node to the canvas for the control.
TCustomTreeView.ExpandSignType |  | Sets the drawing style for the expand / collapse (fold/unfold) indicators for tree nodes.
TCustomTreeView.ExpandSignSize |  | Size of the expand / collapse (fold / unfold) indicators for tree nodes.
TCustomTreeView.ExpandSignWidth |  | Width of the lines drawn for the expand/collapse indicator when using the tvestAngleBracket drawing style.
TCustomTreeView.ExpandSignColor |  | Color used to paint expand / collapse (fold / unfold) indicators for tree nodes.
TTVCustomDrawArrowEvent |  | Specifies an event handler signalled to draw a custom arrow (expand/collapse indicator) for a node on a tree view control.