Hackers Guide to Visual FoxPro 7.0

2017-07-07 02:10:07

Browse, Change, Edit, Set BrStatus

The desire of power in excess caused the angels to fall; the desire of knowledge in excess caused man to fall.

Francis Bacon, Of Goodness and Goodness of Nature, 1625

What can we say about BROWSE? It's a contender for the most complex and powerful command in the language. It's also a contender for the most dangerous—handing an unknowing user a BROWSE without appropriate safeguards is like giving a toddler a magnet and your backup tapes.

CHANGE and EDIT are just other names for BROWSE. They present the same data in a different format. SET BRSTATUS determines whether you get a status bar when you're in a BROWSE, even if you've turned the status bar off.

Usage

BROWSE [FIELDS FieldList] [ NAME ObjectName ] [ FOR lForExpr [ REST ] ] [ KEY eLowKeyValue [ , eHighKeyValue ] ] [ LAST | NOINIT ] [ PREFERENCE PreferenceName ] [ NORMAL ] [ FREEZE FieldName ] [ PARTITION nColumnNumber [ LEDIT ] [ REDIT ] ] [ LPARTITION ] [ LOCK nNumberOfFields ] [ NOLGRID ] [ NORGRID ] [ NOLINK ] [ NOAPPEND ] [ NODELETE ] [ NOEDIT | NOMODIFY ] [ NOMENU ] [ NOOPTIMIZE ] [ NOREFRESH ] [ NOCAPTIONS ] [ NOWAIT ] [ SAVE ] [ TIMEOUT nSeconds ] [ WHEN lWhenExpr ] [ VALID [ :F ] lValidExpr [ ERROR cErrorMessage ] ] [ [ WINDOW DefinitionWindow ] [ IN [ WINDOW ] ContainingWindow | IN SCREEN | IN MACDESKTOP ] ] [ TITLE cTitleText ] [ FONT cFontName [, nFontSize ] ] [ STYLE cStyleCodes ] [ COLOR SCHEME nScheme | COLOR ColorPairList ] [ WIDTH nFieldWidth ] [ NOCLEAR ] [ FORMAT ]

BROWSE has no place in applications. In FoxPro 2.x, you could make some argument for it because there were no good alternatives. You either used BROWSE or lived without its row-at-a-time view of data. In Visual FoxPro, you can use a grid for that view and ignore BROWSE except as a powerful, interactive tool for you, the developer. As for CHANGE/EDIT, it's been obsolete for a long time.

BROWSE does have one clause in Visual FoxPro worth learning. A BROWSE is really just a grid, although you can't find a BROWSE's Parent. The NAME clause lets you manipulate the grid with its PEMs, instead of relying on the same old confusing, complex clauses. The table below maps BROWSE's clauses to the grid and column properties, events and methods that give you the same (or often better) functionality.

Clause	PEM	Purpose
FIELDS	ColumnCount, Columns' ControlSource	Determine which fields appear.
FREEZE	Columns' ReadOnly	Keep fields from being edited. FREEZE specifies a single editable field. ReadOnly lets you decide for each field.
PARTITION, LOCK	Partition	Split the BROWSE/grid into two panes.
LEDIT, REDIT	View	Determine the editing mode for each pane.
LPARTITION	Panel	Determine which pane has focus.
NOCAPTIONS	Columns' Header's Caption	For tables and views in databases, uses the field name regardless of whether a "friendly" caption has been defined.
NOLGRID, NORGRID	GridLines	Determine whether the grid (or a single pane) has lines dividing rows and columns.
NOLINK	PanelLink	Determine whether the two panes are linked together.
NODELETE	DeleteMark	NODELETE prevents the user from deleting records. DeleteMark determines whether a deletion column shows at all. Without it, records can't be deleted.
NOEDIT, NOMODIFY	ReadOnly	Prevent the user from making any changes to data in a grid.
WHEN	When, AfterRowColChange	Determine whether you can enter grid or cell.
VALID	Valid, BeforeRowColChange	Test record for validity as you leave.
FONT	FontName, FontSize	Determine the font used for the BROWSE/grid.
STYLE	FontBold, FontItalic, FontStrikeThru, FontUnderline	Determine the characteristics of the font.
COLORSCHEME, COLOR	BackColor, ForeColor, GridLineColor	Determine the colors used.
WIDTH	Columns' ColumnWidth	Determine the width of individual columns in the grid.

While not every clause has a corresponding property or event, enough of them do to reduce what you have to do with BROWSE itself to pretty minimal—a good thing.

One item here is worth noting. Despite the fact that it's not even documented for VFP 6 and later, the IN MACDESKTOP clause creates a free-floating browse window with its own entry on the taskbar.

Example

* BROWSE is great when you're working interactively. USE Customer BROWSE FIELDS Company_Name,Contact_Name,Phone

Usage

SET BRSTATUS ON | OFF cBrStatus = SET("BRSTATUS")

This one's an antique dating back before Windows and its status bar. It determines what happens when you open a BROWSE and there's no visible status bar. If BRSTATUS is ON, the Xbase-style status bar appears.

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