TXBrowse

The most powerful and versatile data grid control in FiveWin

Fuente: source/classes/xbrowse.prg  |  Parent: TControl  |  Header: XBrowse.ch

Overview

TXBrowse is the flagship data grid control of FiveWin. It renders tabular data from virtually any source -- DBF tables, in-memory arrays, ADO RecordSets, ODBC cursors, or custom data -- through a unified block-based navigation architecture. It virtualizes rendering so that only visible rows are processed, enabling it to handle millions of records without excessive memory consumption.

Key capabilities include:

• Data source abstraction -- one control, many back-ends (DBF/RDD, Array, ADO, ODBC, custom)
• Rich column objects -- each column (TXBrwCol) controls its own header, data formatting, colors, editing, and width
• In-cell editing -- GET, ComboBox, CheckBox, DatePicker, and Spinner editors per column
• Incremental seek / filter -- built-in lIncrFilter seek bar with per-column search
• Multi-select, freeze columns, record selector, marquee styles
• Export to Excel, CSV, clipboard, and printer

Architecture

TXBrowse decouples the visual grid from the underlying data through a set of navigation code blocks. Helper methods like SetRDD(), SetArray(), and SetAdo() simply populate these blocks with the appropriate logic for each data source type.

Column Object: TXBrwCol

Each column in the browse is a TXBrwCol object stored in the aCols array. Columns define what data to display and how to display it.

Key Properties (DATA)

Navigation Blocks

These code blocks form the data abstraction layer. They are set automatically by SetRDD(), SetArray(), SetAdo(), etc., but you can supply custom blocks for specialized data sources.

Key Methods

Commands (XBrowse.ch)

FiveWin provides two command styles for creating TXBrowse controls:

Positioned Command

@ nRow, nCol XBROWSE oBrw ;
   [ OF oWnd ] ;
   [ SIZE nWidth, nHeight ] ;
   [ COLUMNS cCol1, cCol2, ... ] ;
   [ HEADERS cHead1, cHead2, ... ] ;
   [ ALIAS cAlias ] ;
   [ ON DBLCLICK bAction ] ;
   [ FONT oFont ] ;
   [ NOBORDER ]

Quick Browser Command

XBROWSER <cAlias>       // browse a DBF alias
XBROWSER <aArray>       // browse an array
XBROWSER <oRs>          // browse an ADO RecordSet

Code Examples

Example 1: Browsing a DBF Table

#include "FiveWin.ch"
#include "XBrowse.ch"

FUNCTION Main()
   LOCAL oWnd, oBrw

   USE Customer VIA "DBFCDX" NEW

   DEFINE WINDOW oWnd TITLE "Customers" FROM 1, 1 TO 24, 80

   oBrw := TXBrowse():New( oWnd )
   oBrw:nTop    := 0
   oBrw:nLeft   := 0
   oBrw:nRight  := -1   // stretch to right edge
   oBrw:nBottom := -1   // stretch to bottom edge

   oBrw:SetRDD()        // bind to current work area

   // Configure individual columns
   WITH OBJECT oBrw:AddColumn( "ID", FieldBlock( "CUST_ID" ), "99999" )
      :nWidth       := 80
      :nDataStrAlign := AL_RIGHT
   END

   WITH OBJECT oBrw:AddColumn( "First Name", FieldBlock( "FIRSTNAME" ), "@!" )
      :nWidth := 140
      :lEdit  := .T.    // allow in-cell editing
   END

   oBrw:AddColumn( "Last Name",  FieldBlock( "LASTNAME" ),  "@!" )
   oBrw:AddColumn( "City",       FieldBlock( "CITY" ) )
   oBrw:AddColumn( "Balance",    FieldBlock( "BALANCE" ),    "@E 999,999.99" )

   oBrw:nFreeze         := 1       // freeze ID column
   oBrw:lRecordSelector := .T.     // show row indicator
   oBrw:nMarqueeStyle   := MARQSTYLE_HIGHLROW

   oBrw:CreateFromCode()

   oWnd:oClient := oBrw            // fill the window client area
   ACTIVATE WINDOW oWnd

   CLOSE Customer
RETURN NIL

Example 2: Browsing an Array

#include "FiveWin.ch"
#include "XBrowse.ch"

FUNCTION Main()
   LOCAL oWnd, oBrw
   LOCAL aData := { ;
      { "Alice",   "Smith",    28, .T. }, ;
      { "Bob",     "Johnson",  34, .F. }, ;
      { "Charlie", "Williams", 45, .T. }, ;
      { "Diana",   "Brown",    31, .T. }, ;
      { "Edward",  "Jones",    52, .F. }  ;
   }

   DEFINE WINDOW oWnd TITLE "Array Browse" FROM 2, 2 TO 20, 70

   oBrw := TXBrowse():New( oWnd )
   oBrw:SetArray( aData, .F. )   // .F. = do not auto-create columns

   oBrw:aCols := {}
   oBrw:AddColumn( "First",  {|| aData[ oBrw:nArrayAt ][ 1 ] } )
   oBrw:AddColumn( "Last",   {|| aData[ oBrw:nArrayAt ][ 2 ] } )
   oBrw:AddColumn( "Age",    {|| aData[ oBrw:nArrayAt ][ 3 ] }, "999" )
   oBrw:AddColumn( "Active", {|| aData[ oBrw:nArrayAt ][ 4 ] } )

   // Make "Active" column render as a checkbox
   oBrw:aCols[ 4 ]:SetCheck( "CHECK1", "UNCHECK1" )

   oBrw:nMarqueeStyle := MARQSTYLE_HIGHLCELL
   oBrw:CreateFromCode()

   oWnd:oClient := oBrw
   ACTIVATE WINDOW oWnd
RETURN NIL

Example 3: Editable Browse with Column Configuration

#include "FiveWin.ch"
#include "XBrowse.ch"

FUNCTION Main()
   LOCAL oWnd, oBrw, oCol

   USE Invoices VIA "DBFCDX" NEW

   DEFINE WINDOW oWnd TITLE "Editable Invoices"

   @ 0, 0 XBROWSE oBrw OF oWnd ;
      COLUMNS "INVNO", "CUSTNAME", "AMOUNT", "INVDATE", "PAID" ;
      HEADERS "Invoice #", "Customer", "Amount", "Date", "Paid?"

   oBrw:SetRDD()

   // Configure the Amount column
   oCol := oBrw:aCols[ 3 ]
   oCol:cPicture  := "@E 999,999.99"
   oCol:lEdit     := .T.
   oCol:nEditType := EDIT_GET             // edit with a GET control
   oCol:bClrStd   := {|| { CLR_BLACK, CLR_WHITE } }

   // Configure the Date column with a date picker editor
   oCol := oBrw:aCols[ 4 ]
   oCol:lEdit     := .T.
   oCol:nEditType := EDIT_DATE

   // Configure the Paid column as a checkbox
   oCol := oBrw:aCols[ 5 ]
   oCol:SetCheck( "CHECK1", "UNCHECK1" )
   oCol:lEdit := .T.

   oBrw:lFastEdit := .T.   // typing goes straight to edit mode
   oBrw:CreateFromCode()

   oWnd:oClient := oBrw
   ACTIVATE WINDOW oWnd

   CLOSE Invoices
RETURN NIL

Example 4: Incremental Seek / Filter Bar

#include "FiveWin.ch"
#include "XBrowse.ch"

FUNCTION Main()
   LOCAL oWnd, oBrw

   USE Customer INDEX Customer VIA "DBFCDX" NEW

   DEFINE WINDOW oWnd TITLE "Customer Search"

   oBrw := TXBrowse():New( oWnd )
   oBrw:SetRDD()

   oBrw:AddColumn( "Name",    FieldBlock( "NAME" ) )
   oBrw:AddColumn( "City",    FieldBlock( "CITY" ) )
   oBrw:AddColumn( "Phone",   FieldBlock( "PHONE" ) )
   oBrw:AddColumn( "Balance", FieldBlock( "BALANCE" ), "@E 999,999.99" )

   // Enable the incremental filter bar
   oBrw:lIncrFilter := .T.

   // Custom seek block -- performs an indexed seek on the NAME field
   oBrw:bSeek := {|cSeek| ( oBrw:cAlias )->( DbSeek( cSeek, .T. ) ) }

   oBrw:nMarqueeStyle   := MARQSTYLE_HIGHLROW
   oBrw:lRecordSelector := .T.

   oBrw:CreateFromCode()
   oWnd:oClient := oBrw
   ACTIVATE WINDOW oWnd

   CLOSE Customer
RETURN NIL

Tips and Best Practices

• Always call CreateFromCode() after configuring data source, columns, and visual properties.
• Use oWnd:oClient := oBrw to make the browse auto-resize with the window.
• Avoid lFastEdit with navigation-heavy UIs -- it intercepts character keys that would otherwise trigger seeks or keyboard shortcuts.
• For incremental seek on a DBF, ensure the table has an active index on the column you are searching.
• Column bClrEdit controls the colors of the cell while it is being edited (foreground/background block). This is separate from bClrStd which controls display-mode colors.
• Double-buffer painting: TXBrowse paints to an off-screen bitmap, then blits to screen. This eliminates flicker but means you should call Refresh() -- not Invalidate() -- to force a redraw.
• For very large arrays, consider using SetRDD() with a temporary DBF instead, as array navigation does not virtualize seeks.

Ver También

• TControl -- parent class
• TDatabase -- high-level DBF wrapper often used with TXBrowse
• TRecordSet (ADO) -- ADO data source for SetAdo()
• TGet -- used internally for cell editing