TCustomTreeView.ExpandSignType

Sets the drawing style for the expand / collapse (fold/unfold) indicators for tree nodes.

Declaration

Source position: comctrls.pp line 3744

Description

ExpandSignType is a TTreeViewExpandSignType property with the drawing style used for expand / collapse indicators on tree nodes in the control. It contains a value from the TTreeViewExpandSignType enumeration, such as:

tvestTheme

Uses theme element details for the platform to draw the indicators.

tvestPlusMinus

Uses '+' and '-' symbols to draw the indicators.

tvestArrow

Uses an unfilled arrow for the indicators.

tvestArrowFill

Uses a filled arrow for the indicators.

tvestAngleBracket

Uses chevrons (angle brackets) for the indicators.

The default value for the property is tvestTheme, and causes the DrawElement method in ThemeServices to be used to render the indicator. Other values cause methods in the control to be called to render the indicator. Changing the value for the property causes the control to be redrawn.

ExpandSignType is used in the DoPaintNode method to determine the drawing style for the expand / collapse indicator for a tree node that has child nodes. It also determines the scaling mechanism needed for themed versus non-themed drawing styles.

Use ExpandSignSize to set the default dimensions for the indicator before it is scaled for the theme or font size. Use ExpandSignColor to set the fill color for a filled arrow-style indicator. Use ExpandSignWidth to set the line width used for a chevron or angle bracket-style indicator.

See also