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

TCustomComboBox.OnMeasureItem

Handler invoked when the height for an item is needed.

Declaration

Source position: stdctrls.pp line 401

protected property TCustomComboBox.OnMeasureItem : TMeasureItemEvent
  read FOnMeasureItem
  write FOnMeasureItem;

Description

OnMeasureItem is a TMeasureItemEvent property with the event handler signalled to get the height for an item displayed in the list box for the control.

OnMeasureItem is signalled (when assigned) from the MeasureItem method. MeasureItem (and OnMeasureItem) are used when the Style property indicates that the control uses a variable height for each item displayed in the list box. OnMeasureItem occurs when the LM_MeasureItem message is handled for the control.

Use the Index argument to get the value in Items examined in the event handler. Use ItemWidth to determine the maximum width allowed for the variable height item. Canvas can be used to get text metrics for the Font used in the control. Update the AHeight argument with the height calculated for the item.

Use ItemHeight for the item height used for fixed height drawing styles.

See also

TCustomComboBox.MeasureItem

  

Gets the height for an item in the drop-down list.

TCustomComboBox.Style

  

Controls the appearance and behavior for the combo-box.

TCustomComboBox.ItemHeight

  

The default height of an item in the drop-down for the control.

TCustomComboBox.ItemWidth

  

The minimum width of the items in the drop-down list.

TCustomComboBox.Canvas

  

Provides access to the drawing surface for the control.

TMeasureItemEvent

  

Specifies an event handler used to get the Height for a single item in an owner-drawn list box or combo-box.


Version 3.2 Generated 2024-02-25 Home