SysWin Gui UpDown

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UpDown

Reads and sets an up-down control's position, range, base, buddy window and acceleration.

An up-down control (a spin button) is a pair of arrows that step a number up or down within a range. It is nearly always paired with a buddy window, an edit control beside it: with the UDS_SETBUDDYINT style the control writes its position into the buddy's text, and reads the position back from it. Create one with CWindow.AddControl( "UpDown", ... ), which gives it UDS_WRAP, UDS_ARROWKEYS, UDS_ALIGNRIGHT and UDS_SETBUDDYINT, base 10 and position 0. Every function here takes the control's handle first and is written with the namespace: UpDown.GetPos32( hUpDown ).

AddControl leaves the range as the control's own default: 100 as the minimum and 0 as the maximum, so the up arrow makes the number smaller. Call SetRange32 with the range you want, UpDown.SetRange32( h, 0, 100 ).

Each click sends the parent a WM_NOTIFY with UDN_DELTAPOS before the position changes; the NMUPDOWN it carries has the current position and the proposed change, and returning nonzero cancels it. Then the parent receives WM_VSCROLL (or WM_HSCROLL for UDS_HORZ).

Importing

#import "sys/win"
#import "sys/win/gui"
using win, gui

Example

An edit control with an up-down control attached, counting from 1 to 50 in steps that grow from 1 to 5 while an arrow is held down; the caption follows the value.

#import "sys/win"
#import "sys/win/gui"
using win, gui

const IDC_EDIT = 101
const IDC_UPDOWN = 102

declare function WndProc( byval hwnd as HWND, byval uMsg as UINT, byval wParam as WPARAM, byval lParam as LPARAM ) as LRESULT

function main() as long
    SetProcessDpiAwareness( PROCESS_SYSTEM_DPI_AWARE )
    dim pWindow as CWindow = "UpDownDemo"
    dim hWin as HWND = pWindow.Create( NULL, "Copies: 1", @WndProc )
    pWindow.SetClientSize( 300, 100 )
    pWindow.Center()
    pWindow.AddControl( "Label", hWin, -1, "Copies:", 40, 40, 70, 22 )
    dim hEdit as HWND = pWindow.AddControl( "Edit", hWin, IDC_EDIT, "", 120, 38, 70, 24, _
                                            WS_VISIBLE or WS_TABSTOP or ES_NUMBER or ES_RIGHT )
    dim hUpDown as HWND = pWindow.AddControl( "UpDown", hWin, IDC_UPDOWN )
    UpDown.SetBuddy( hUpDown, hEdit )
    UpDown.SetRange32( hUpDown, 1, 50 )
    UpDown.SetPos32( hUpDown, 1 )
    dim acc(1) as UDACCEL
    acc(0).nSec = 0 : acc(0).nInc = 1
    acc(1).nSec = 2 : acc(1).nInc = 5
    UpDown.SetAccel( hUpDown, 2, @acc(0) )
    return pWindow.DoEvents( SW_NORMAL )
end function

function WndProc( byval hwnd as HWND, byval uMsg as UINT, byval wParam as WPARAM, byval lParam as LPARAM ) as LRESULT
    select case uMsg
        case WM_VSCROLL
            dim hUpDown as HWND = cast( HWND, lParam )
            if hUpDown = GetDlgItem( hwnd, IDC_UPDOWN ) then
                SetWindowText( hwnd, "Copies: " & UpDown.GetPos32( hUpDown ) )
            end if
            return 0
        case WM_DESTROY
            PostQuitMessage( 0 )
            return 0
    end select
    return DefWindowProcW( hwnd, uMsg, wParam, lParam )
end function

end main()

Functions

Function	Does
GetPos32	Returns the position as a 32-bit value.
SetPos32	Sets the position as a 32-bit value.
GetPos	Returns the 16-bit position and an error flag in one value.
SetPos	Sets the position as a 16-bit value.
GetRange32	Reads the minimum and maximum, 32 bits each.
SetRange32	Sets the minimum and maximum, 32 bits each.
GetRange	Returns the 16-bit maximum and minimum in one value.
SetRange	Sets the maximum and minimum, 16 bits each.
GetBuddy	Returns the buddy window.
SetBuddy	Sets the buddy window.
GetBase	Returns whether the buddy shows decimal or hexadecimal.
SetBase	Makes the buddy show decimal or hexadecimal.
GetAccel	Reads how the step grows while an arrow is held.
SetAccel	Sets how the step grows while an arrow is held.

Reference

GetPos32

function GetPos32( byval hUpDown as HWND, byval pfError as long ptr = NULL ) as long

Returns the position. When the control has a buddy with UDS_SETBUDDYINT, the position is first read back from the buddy's text, so it includes what the user typed.

Parameter	Meaning
pfError	Optional; receives 0 when the position is good and nonzero when it is not, for instance when the buddy's text is not a number. It is also nonzero for a control that has no buddy.

Returns the position.

Example

dim nErr as long
dim n as long = UpDown.GetPos32( hCtrl, @nErr )
if nErr = 0 then print "value:"; n

Microsoft Learn: UDM_GETPOS32

SetPos32

function SetPos32( byval hUpDown as HWND, byval nPos as long ) as long

Sets the position, and with UDS_SETBUDDYINT the buddy's text. A value outside the range is moved to the nearer end.

Returns the previous position.

Example

UpDown.SetPos32( hCtrl, 10 )

Microsoft Learn: UDM_SETPOS32

GetPos

function GetPos( byval hUpDown as HWND ) as long

The 16-bit form of GetPos32. The value carries two things: the position in the low word and an error flag in the high word, nonzero when the position is not good (and for a control without a buddy). With position 42 and a good buddy it is 42; with position 300 and no buddy it is &h1012C.

Returns the position in the low word and the error flag in the high word.

Example

dim r as long = UpDown.GetPos( hCtrl )
if HIWORD( r ) = 0 then print "value:"; cast( short, LOWORD( r ) )

Microsoft Learn: UDM_GETPOS

SetPos

function SetPos( byval hUpDown as HWND, byval nPos as short ) as long

The 16-bit form of SetPos32.

Returns the previous position.

Example

UpDown.SetPos( hCtrl, 5 )

Microsoft Learn: UDM_SETPOS

GetRange32

sub GetRange32( byval hUpDown as HWND, byval pLow as long ptr, byval pHigh as long ptr )

Reads the range: *pLow receives the minimum, *pHigh the maximum. Either pointer may be NULL. Straight after AddControl they are 100 and 0.

Example

dim as long lo, hi
UpDown.GetRange32( hCtrl, @lo, @hi )
print "from"; lo; " to"; hi

Microsoft Learn: UDM_GETRANGE32

SetRange32

sub SetRange32( byval hUpDown as HWND, byval iLow as long, byval iHigh as long )

Sets the range, as 32-bit values. The up arrow moves towards iHigh; a minimum larger than the maximum makes the up arrow count down.

Example

UpDown.SetRange32( hCtrl, 0, 1000 )

Microsoft Learn: UDM_SETRANGE32

GetRange

function GetRange( byval hUpDown as HWND ) as long

The 16-bit form of GetRange32: the maximum in the low word and the minimum in the high word. After AddControl it is &h640000 (maximum 0, minimum 100).

Returns the packed range.

Example

dim r as long = UpDown.GetRange( hCtrl )
print "minimum"; cast( short, HIWORD( r ) ); " maximum"; cast( short, LOWORD( r ) )

Microsoft Learn: UDM_GETRANGE

SetRange

sub SetRange( byval hUpDown as HWND, byval nUpper as short, byval nLower as short )

The 16-bit form of SetRange32, with the maximum first: nUpper is the maximum and nLower the minimum, so SetRange( h, 10, 1 ) gives 1 to 10. Neither may be farther than 32767 from the other.

Example

UpDown.SetRange( hCtrl, 10, 1 )   ' 1 to 10

Microsoft Learn: UDM_SETRANGE

GetBuddy

function GetBuddy( byval hUpDown as HWND ) as HWND

Returns the buddy window, or NULL when there is none.

Example

dim hBuddy as HWND = UpDown.GetBuddy( hCtrl )
if hBuddy then print "buddy text: "; GetWindowText( hBuddy )

Microsoft Learn: UDM_GETBUDDY

SetBuddy

function SetBuddy( byval hUpDown as HWND, byval hwndBuddy as HWND ) as HWND

Makes hwndBuddy the buddy. With UDS_ALIGNRIGHT or UDS_ALIGNLEFT the up-down control moves itself to that edge of the buddy, which is narrowed to make room, so AddControl( "UpDown", ... ) needs no position or size.

Returns the previous buddy, or NULL.

Example

dim pWindow as CWindow ptr = CWindowPtr( hwnd )
UpDown.SetBuddy( hCtrl, pWindow->AddControl( "Edit", hwnd, 200, "0", 20, 20, 60, 22 ) )

Microsoft Learn: UDM_SETBUDDY

GetBase

function GetBase( byval hUpDown as HWND ) as long

Returns 10 when the buddy shows the position in decimal, 16 when in hexadecimal.

Example

print "base"; UpDown.GetBase( hCtrl )

Microsoft Learn: UDM_GETBASE

SetBase

function SetBase( byval hUpDown as HWND, byval nBase as long ) as long

Makes the buddy show the position in decimal (nBase 10) or hexadecimal (16). Hexadecimal numbers are shown without a sign. Any other base is refused.

Returns the previous base, or 0 when nBase is neither 10 nor 16.

Example

UpDown.SetBase( hCtrl, 16 )

Microsoft Learn: UDM_SETBASE

GetAccel

function GetAccel( byval hUpDown as HWND, byval cAccels as DWORD, byval pAccels as UDACCEL ptr ) as long

Copies up to cAccels acceleration steps into the array at pAccels. Each UDACCEL says that after nSec seconds of holding an arrow the position moves by nInc per step.

Returns the number of acceleration steps the control has, which can be more than were copied.

Example

dim acc(7) as UDACCEL
dim n as long = UpDown.GetAccel( hCtrl, 8, @acc(0) )
for i as long = 0 to n - 1 : print acc(i).nSec; "s:"; acc(i).nInc : next

Microsoft Learn: UDM_GETACCEL

SetAccel

function SetAccel( byval hUpDown as HWND, byval cAccels as DWORD, byval pAccels as UDACCEL ptr ) as boolean

Replaces the acceleration steps with the cAccels entries of the array at pAccels, in order of increasing nSec. The control copies them, so the array need not outlive the call.

Returns true on success.

Example

dim acc(2) as UDACCEL
acc(0).nSec = 0 : acc(0).nInc = 1
acc(1).nSec = 2 : acc(1).nInc = 10
acc(2).nSec = 4 : acc(2).nInc = 100
UpDown.SetAccel( hCtrl, 3, @acc(0) )

Microsoft Learn: UDM_SETACCEL

See also

• sys/win/gui
• CWindow for AddControl( "UpDown", ... )
• Edit for the buddy
• TrackBar
• gui macros and helpers for reading WM_NOTIFY