TDBCombo

Source: source/classes/dbcombo.prg

Inherits from: TComboBox

TDBCombo is a database-aware ComboBox that displays values from a DBF field and can return a different value to the bound variable. It supports an incremental search as the user types, and can auto-populate its items from the database when no explicit array is provided.

Key DATA Members

DATA	Type	Description
`cAlias`	Character	Workarea alias for the database table (default: current alias)
`cFldList`	Character	Field name whose values are displayed in the combo
`cFldItem`	Character	Field name whose value is returned to the bound variable
`aList`	Array	Array of display strings shown in the dropdown
`aItems`	Array	Array of return values corresponding to aList entries
`cSearchKey`	Character	Incremental search buffer for keyboard navigation

Methods

Method	Description
`New( nRow, nCol, bSetGet, aItems, nW, nH, oWnd, nHelpId, bChange, bValid, nClrFore, nClrBack, lPixel, oFont, cMsg, lUpdate, bWhen, lDesign, acBitmaps, bDrawItem, cAlias, cFldItem, cFldList, aList, nHGet )`	Create a new DBF-aware ComboBox
`ReDefine( nId, bSetGet, aItems, oWnd, ... )`	Redefine from a dialog resource
`Fill()`	Populate aItems and aList from the database (called automatically on New/ReDefine if no explicit arrays given)
`Refill()`	Re-read the database and repopulate the combo items
`SetItems( aItems, aList, lChanged )`	Set display and return value arrays manually
`Add( cItem, nAt, cList )`	Add an item to the combo at position nAt
`Del( nAt )`	Delete item at position nAt
`ListGet()`	Return the selected element of ::aList
`KeyChar( nKey, nFlags )`	Incremental search keyboard handler
`Update()`	Refresh the display from the current bound variable

Example: Combo Linked to Customer City Field

#include "FiveWin.ch"

function Main()

   local oWnd, oCombo, cCity := Space( 20 )

   use Customer shared new
   index on field->city to tmpCity

   DEFINE WINDOW oWnd TITLE "TDBCombo Demo" SIZE 400, 150

   @ 30, 30 DBCOMBO oCombo VAR cCity ;
      ITEMS FIELD->city ;
      OF oWnd ;
      SIZE 150, 120

   ACTIVATE WINDOW oWnd CENTERED

   use

return nil

Notes

TDBCombo can display one field value while returning a different one. For example, show department names (cFldList) but return department IDs (cFldItem).
Incremental search is supported: typing characters filters the list. Pressing Space resets the search buffer.
When neither aItems nor aList is provided, the constructor calls Fill() to auto-populate from the database fields.
The combo data can be manually refreshed with Refill() when the underlying database records change.

TDBCombo

Key DATA Members

Methods

Example: Combo Linked to Customer City Field

Notes

See Also