Form, Formset

Hacker’s Guide to Visual FoxPro
An irreverent look at how Visual FoxPro really works. Tells you the inside scoop on every command, function, property, event and method of Visual FoxPro.

Form, Formset

Forms and formsets are container classes that, from one point of view, put the “visual” in Visual FoxPro. Formsets contain forms and toolbars. Forms contain controls.

Form

Property	Value	Meaning
ActiveControl	Object	A reference to the control on the form that currently has focus.
AlwaysOnBottom	Logical	Determines whether this form always stays underneath other windows, like a kind of wallpaper.
AlwaysOnTop	Logical	Determines whether this form stays on top of other windows, even when it doesn't have focus.
AutoCenter	Logical	Determines whether the form automatically centers itself when it first appears. Also allows you to center a form at any time.
BorderStyle	Numeric	Determines the type of border of the form. Also determines whether the form can be resized.
BufferMode	Numeric	Determines the type of buffering used for cursors in the form's data environment, unless the cursors override this setting individually.
Caption	Character	The title that appears in the form's border.
ClipControls	Logical	Determines what gets redrawn when the form is resized or controls are moved about.
Closable	Logical	Determines whether the form can be closed by the operator with the mouse and Ctrl+F4.
ContinuousScroll	Logical	Determines how the form behaves when you use the scrollbars.
ControlBox	Logical	Determines whether the form has a Windows standard control menu.
ControlCount	Numeric	The number of controls currently on the form.
Controls	Collection	References to the controls currently on the form.
CurrentX, CurrentY	Numeric	The position of the drawing cursor on the form.
DataSession	Numeric	Determines whether the form has its own private data session.
DataSessionId	Numeric	The data session being used by the form.
DefOLELCId	Numeric	Indicates the default locale ID (language) for OLE objects used in the form.
Desktop	Logical	Determines whether the form is contained in the main Visual FoxPro window.
DrawMode	Numeric	Determines the way colors work in drawing methods.
DrawStyle	Numeric	The type of lines drawn by drawing methods.
DrawWidth	Numeric	The width of lines drawn by drawing methods.
FillColor	Numeric	The color used to fill figures drawn with drawing methods.
FillStyle	Numeric	The pattern used to fill figures drawn with drawing methods.
HalfHeightCaption	Logical	Determines whether the title bar uses a FoxPro/DOS compatibility style or the standard Windows style. Although the two choices are nearly indistinguishable visually, there are functional differences. Keep this property set to .F.
HScrollSmallChange	Numeric	Determines how far the form scrolls on a single click on a horizontal scroll arrow.
hWnd	Numeric	The Windows window handle of the form.
Icon	Character	The icon file used in the form's title bar.
KeyPreview	Logical	Determines whose KeyPress event fires when the user presses a key—the form's or the control's.
LockScreen	Logical	Determines whether the form is visually updated immediately when some kinds of changes are made to the form or its controls.
MaxButton, MinButton	Logical	Determines whether the form has maximize and minimize buttons.
MaxHeight, MaxWidth	Numeric	The largest size to which the user can resize the form.
MaxLeft, MaxTop	Numeric	The position at which the form appears when maximized.
MDIForm	Logical	Determines whether the form behaves like an MDI (multiple document interface) form.
MinHeight, MinWidth	Numeric	The smallest size to which the user can resize the form.
Movable	Logical	Determines whether the user can move the form.
Objects	Collection	Contains a reference to every object contained within the form.
Picture	Character	File name of a picture to be tiled as wallpaper on the form.
ReleaseType	Numeric	Indicates how the form was released.
ScaleMode	Numeric	The measurement system used for the form.
ScrollBars	Numeric	Determines what kind of scrollbars, if any, the form has.
ShowInTaskBar	Logical	Determines whether the top-level form appears in the task bar at runtime. Ignored if the ShowWindow property is anything other than 2 (top-level form).
ShowTips	Logical	Determines whether tooltips are displayed.
ShowWindow	Numeric	Determines whether the form is a child of the VFP window, a top-level form itself, or a child of a top-level form.
TitleBar	Numeric	Determines whether the form has a title bar.
ViewPortHeight, ViewPortWidth	Numeric	Indicate the size of the viewport into the form, that is, the size of the visible area.
ViewPortLeft, ViewPortTop	Numeric	Indicate the top left corner of the portion of the form currently visible.
VScrollSmallChange	Numeric	Determines how far the form scrolls on a single click on a vertical scroll arrow.
WindowState	Numeric	Is the form normal size, maximized or minimized?
WindowType	Numeric	Indicates whether the form is modal or modeless. Also used to indicate READ compatibility.

Event	Purpose
Activate, Deactivate	Fire when the form gains or loses focus.
Load, Unload	First and last events to fire.
Moved	Fires when the form is moved.
Paint	Fires when part of the form is exposed and has to be redrawn.
QueryUnload	Fires when the form is released. Issue NODEFAULT in this method to prevent the form from being destroyed.
Resize	Fires when the form is resized.
Scrolled	Fires when the form's scrollbars are used.

Method	Purpose
Box, Circle, Line	Drawing methods that put figures on the form.
Cls	Drawing method that clears figures and text from the form.
Draw	Repaints the form.
Point	Returns the color of a particular point.
Print	Drawing method that puts text on the form.
PSet	Sets the color of a particular point.
Release	Destroys the form.
SaveAs	Creates a new SCX based on the currently displayed form.
SaveAsClass	Creates a new class in a VCX based on the currently displayed form.
SetViewPort	Sets the ViewPortLeft and ViewPortTop properties to determine which portion of the form is visible.
Show, Hide	Make the form visible and invisible. Show also activates the form initially.
TextHeight, TextWidth	Return the height and width of a specified string in the current form's font.

FormSet

Property	Value	Meaning
ActiveForm	Object	Reference to the form in the set that has focus.
AutoRelease	Logical	Indicates whether the formset object should be released when all the forms in the set have been released.
BufferMode	Numeric	Determines the type of buffering used by default for cursors in the formset.
DataSession	Numeric	Determines whether the formset has its own private data session.
DataSessionId	Numeric	The data session being used by the formset.
FormCount	Numeric	The number of forms in the set.
Forms	Collection	References to the forms in the set.
Objects	Collection	Contains a reference to every object contained within the formset.
ReadCycle, ReadLock, ReadMouse, ReadObject, ReadSave, ReadTimeOut, WindowList	Various	Special properties used only in forms converted from FoxPro 2.x screens. They correspond to various READ clauses.
WindowType	Numeric	Indicates whether the formset is modal or modeless. Also used to indicate READ compatibility.

Event	Purpose
Activate, Deactivate	Fire when the formset gains or loses focus.
Load, Unload	First and last events to fire in the formset.
ReadActivate, ReadDeactivate, ReadShow, ReadValid, ReadWhen	Events to model FoxPro 2.x READ clauses. Used only for forms converted from FoxPro 2.x screens.

Method	Purpose
Release	Destroys the formset.
Show, Hide	Makes the formset visible and invisible. Show also activates the formset initially.

Forms and formsets are different from other objects in Visual FoxPro for several reasons. First, there are two different ways to create and activate them. Like other objects, they can be stored as classes, then instantiated with CREATEOBJECT() or NewObject(). However, individual form and formset instances can also be stored in SCX files and executed with DO FORM. (Note that form and formset classes stored in VCX libraries do not include a data environment, while forms stored in SCXs do.)

The second difference is that forms and formsets have Load and Unload methods that fire before Init and after Destroy, respectively. Load lets you open databases and tables before the controls in a form are instantiated and initialized, so you can bind controls to fields. Similarly, the controls need to be destroyed before you can close the tables—Unload (which follows the Destroys for the controls) gives you that opportunity. (You use Load and Unload for table handling only if you’re not letting the data environment automatically open and CLOSE TABLES. Since you can’t save a data environment with a form or formset class, there are some good reasons to use Load and Unload this way.)

The firing sequence is confusing, though, because parameters to a form or formset are normally passed to the Init method, just like other controls, even though other events fire first. (For forms converted from 2.x, parameters go to the Load method.)

It took us awhile to catch on that windows you create with DEFINE WINDOW are really forms, too. In fact, there’s no reason ever to define a window again. Just instantiate a form and you can put whatever you want in it. There’s nothing to keep you from putting a Browse in an instantiated form, for example (not that we use Browse anything but interactively in Visual FoxPro).

Example

DEFINE CLASS HackForm AS Form
   Caption = "Hacker's Example Form"
   BackColor = RGB(0,0,255)
   ForeColor = RGB(255,255,255)

   PROCEDURE Resize
      LOCAL cMessage
      cMessage = "Hey, watch it, buster!"
      This.Cls
      This.CurrentX = (This.Width-This.TextWidth(cMessage))/2
      This.CurrentY = This.Height/2
      This.Print(cMessage)
   ENDPROC

   PROCEDURE Moved
      LOCAL cMessage
      cMessage = "Who do you think you're moving?"
      This.Cls
      This.FillColor = RGB(255,0,0)
      This.FillStyle = 0
      This.Box(This.Width/4, This.Height/4,;
               3*This.Width/4,3*This.Height/4 )
      This.CurrentY = This.Height/2
      This.CurrentX = This.Width/4 + 2
      This.Print(cMessage)
   ENDPROC
ENDDEFINE

Form, Formset

Form

FormSet

Example

See Also