Form Function

Purpose

Returns a Form object for a given window handle or window number.

Syntax

Set form = Form( wh% )

form:Form Object
wh%:iexp

Description

Form(handle) returns a Form object for a given window handle. When the handle can't be found the return value is Nothing. This type of function Form() is in particular useful in the event subs _MessageProc and Screen_KeyPreview.

Form(n) designates the window-form created with OpenW or ChildW. Where n is a number between 0 and 31, the name of froms is predefined as Win_n, where n is a number between 0 and 31. This name is introduced in the global variable list and is accessible throughout the program. These variable names can be used in accessing properties, methods, and events. For instance, Win_1.Name returns "Win_1". Windows created with a number greater than 31 don't declare global variable names implicitly and can only be accessed using Form(n).Name. However, there is no variable name introduced, but their name still consists of "Win_n", where n is the window number.

Example 1:

Dim frm As Form

OpenW 1

Set frm = Form(Win_1.hWnd)

frm.Caption = "Window 1"

Form(1).BackColor = $8000000f

Win_1.FontTransparent = True

Print frm.Name

Do : Sleep : Until Win_1 Is Nothing

// Using frm is the Do...Until statement will cause the program into an infinite loop

// ...as closing Win_1 does not set frm to Nothing but does delete the object so

// ...that frm can no longer be accessed.

Trace IsNothing(frm)

Set frm = Nothing

Example 2:

Global key$, i%

Form test = , 0, 0, _X / 2, _Y / 2

For i% = 1 To 15 : OpenW i% : Next

PrintScroll = True

Try

Print Form(GetActiveWindow()).Name

Catch

EndCatch

Sleep

Until key$ <> ""

For i% = 1 To 15 : CloseW i% : Next

test.Close

Sub Screen_KeyPreview(hWnd%, uMsg%, wParam%, lParam%, Cancel?)

If uMsg% = WM_CHAR Then key$ = wParam%

EndSub

Remarks

The OCX(handle) function does the same as Form(Handle) for an Ocx control by returning a general Control object for a given window handle.