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

# TCustomComboBox.KeyUp

Handles AutoComplete and AutoSelect for the control.

## Declaration

Source position: stdctrls.pp line 388

`protected procedure TCustomComboBox.KeyUp(`
`var Key: Word;`
`Shift: TShiftState`
`); override;`

## Arguments

`Key` |  | Virtual key code examined in the method.
`Shift` |  | Shift, Alt, or Ctrl modifier for the key code.

## Description

KeyUp is an overridden method in TCustomComboBox, and calls the inherited method on entry.

KeyUp ensures that the VK_RETURN key code causes SelectAll to be called when AutoCompletion or AutoSelect is enabled for the control. AutoSelected is set to True when the values in SelText and Text are the same.

In addition, alphanumeric key codes are used to perform AutoComplete text location using the options enabled in the AutoCompleteText property. The values in Text, SelStart, and SelLength are updated (when needed) and the Select method is called to reflect the operation. If the key causes the auto-completed text to differ from the value in Text, ItemIndex is updated to reflect the auto-completed text value.

KeyUp is called when TLMKeyUp control messages are processed in the handlers for the control.

## See also

TCustomComboBox.AutoSelect |  | Selects the entire content of the edit box when the control receives the focus.
TCustomComboBox.AutoSelected |  | True indicates that the selection was marked automatically by the control.
TCustomComboBox.AutoComplete |  | Positions the list box using partial text matching.
TCustomComboBox.AutoCompleteText |  | Options for the behavior of the Auto-Complete feature.
TCustomComboBox.Text |  | The value in the edit box for the control.
TCustomComboBox.SelText |  | The selected text in the edit box for the control.
TCustomComboBox.SelStart |  | zero-based index to the UTF-8 character at the beginning of the selected text in the edit box.
TCustomComboBox.SelLength |  | The number of selected UTF-8 characters in the edit box.
TCustomComboBox.Select |  | Signals the OnSelect event handler when ItemIndex is changed.
TCustomComboBox.ItemIndex |  | The index of the currently selected item, or -1 if no item is selected.
TWinControl.KeyUp |  | Signals the OnKeyUp event handler (when assigned).