ACC2000: How to Use the GetSystemMetrics() API Call

The information in this article applies to:

Microsoft Access 2000
Microsoft Visual Basic for Applications

Advanced: Requires expert coding, interoperability, and multiuser skills.

This article applies to a Microsoft Access database (.mdb) and a Microsoft Access project (.adp).

SUMMARY

In the Windows environment, various display resolutions may cause screens to appear out of proportion. As a developer, you can get the width and height of various elements of the window display by using the Windows application programming interface (API) function GetSystemMetrics(). Incorporating this function into an Access application gives you more information for designing the user interface. This article describes the GetSystemMetrics() API function and shows you how to call the function from Access.

MORE INFORMATION

The Windows GetSystemMetrics() API function retrieves information about the system metrics (the width and height of various display elements of a particular window). The GetSystemMetrics() function can also return flags that indicate whether a mouse is present or if the meaning of the left and right mouse buttons have been reversed. System metrics are dependent upon the system display and may vary from display to display.

To use the GetSystemMetrics() functions, follow these steps:

Create a new Access database.
Create a new module.
Place the following Declare statement in the Declarations section of a module:

Declare Function GetSystemMetrics& Lib "User32" (ByVal nIndex&)

NOTE: This Declare statement is case-sensitive.

Depending on which window property you want to determine, you must define the correct constant to pass to the GetSystemMetrics() function. Following are sample declarations of the constants and their meaning. Constants by default are Private. If you want to place these constants in a global module so that they are available to the entire application, add Public to the beginning of the constant statement (Public Const SM_CXSCREEN = 0). For a complete list of the constants available for Windows 95 and 98, please refer to the Win32 Software Development Kit.

Starting on the next line after the Declare statement, type the following functions in the Declarations section:

Const SM_CXSCREEN = 0        ' Width of screen

Const SM_CYSCREEN = 1        ' Height of screen

Const SM_CXFULLSCREEN = 16   ' Width of window client area

Const SM_CYFULLSCREEN = 17   ' Height of window client area

Const SM_CYMENU = 15         ' Height of menu

Const SM_CYCAPTION = 4       ' Height of caption or title

Const SM_CXFRAME = 32        ' Width of window frame

Const SM_CYFRAME = 33        ' Height of window frame

Const SM_CXHSCROLL = 21      ' Width of arrow bitmap on

                             '  horizontal scroll bar

Const SM_CYHSCROLL = 3       ' Height of arrow bitmap on

                             '  horizontal scroll bar

Const SM_CXVSCROLL = 2       ' Width of arrow bitmap on

                             '  vertical scroll bar

Const SM_CYVSCROLL = 20      ' Height of arrow bitmap on

                             '  vertical scroll bar

Const SM_CXSIZE = 30         ' Width of bitmaps in title bar

Const SM_CYSIZE = 31         ' Height of bitmaps in title bar

Const SM_CXCURSOR = 13       ' Width of cursor

Const SM_CYCURSOR = 14       ' Height of cursor

Const SM_CXBORDER = 5        ' Width of window frame that cannot

                             '  be sized

Const SM_CYBORDER = 6        ' Height of window frame that cannot

                             '  be sized

Const SM_CXDOUBLECLICK = 36  ' Width of rectangle around the

                             '  location of the first click. The

                             '  second click must occur in the

                             '  same rectangular location.

Const SM_CYDOUBLECLICK = 37  ' Height of rectangle around the

                             '  location of the first click. The

                             '  second click must occur in the

                             '  same rectangular location.

Const SM_CXDLGFRAME = 7      ' Width of dialog frame window

Const SM_CYDLGFRAME = 8      ' Height of dialog frame window

Const SM_CXICON = 11         ' Width of icon

Const SM_CYICON = 12         ' Height of icon

Const SM_CXICONSPACING = 38  ' Width of rectangles the system

                             ' uses to position tiled icons

Const SM_CYICONSPACING = 39  ' Height of rectangles the system

                             ' uses to position tiled icons

Const SM_CXMIN = 28          ' Minimum width of window

Const SM_CYMIN = 29          ' Minimum height of window

Const SM_CXMINTRACK = 34     ' Minimum tracking width of window

Const SM_CYMINTRACK = 35     ' Minimum tracking height of window

Const SM_CXHTHUMB = 10       ' Width of scroll box (thumb) on

                             '  horizontal scroll bar

Const SM_CYVTHUMB = 9        ' Width of scroll box (thumb) on

                             '  vertical scroll bar

Const SM_DBCSENABLED = 42    ' Returns a non-zero if the current

                             '  Windows version uses double-byte

                             '  characters, otherwise returns

                             '  zero

Const SM_DEBUG = 22          ' Returns non-zero if the Windows

                             '  version is a debugging version

Const SM_MENUDROPALIGNMENT = 40

                             ' Alignment of pop-up menus. If zero,

                             '  left side is aligned with

                             '  corresponding left side of menu-

                             '  bar item. If non-zero, left side

                             '  is aligned with right side of

                             '  corresponding menu bar item

Const SM_MOUSEPRESENT = 19   ' Non-zero if mouse hardware is

                             '  installed

Const SM_PENWINDOWS = 41     ' Handle of Pen Windows dynamic link

                             '  library if Pen Windows is

                             '  installed

Const SM_SWAPBUTTON = 23     ' Non-zero if the left and right

' mouse buttons are swapped

Save the new module as MetricsCode.
Create a new blank form with the following properties:

   Form: Test1

   -------------------------

   Caption: TestForm

   ControlSource: &amp;none&gt;

   Command button

   ---------------------------

   Name: Button0

   Caption: My Button

Set the OnClick property of the Button0 command button to the following event procedure:

'The following call returns the height of the form's caption bar

Private Sub Command0_Click()

  Dim HeightY As String

  HeightY = GetSystemMetrics(SM_CYCAPTION)

  MsgBox HeightY

End Sub

View the form in Form view and click the command button. Note that you see the height of the form's caption bar in a message box.

REFERENCES

For more information about declaring functions, in the Visual Basic Editor, click Microsoft Visual Basic Help on the Help menu, type Declare Statement in the Office Assistant or the Answer Wizard, and then click Search to view the topic.

For more information about constants, in the Visual Basic Editor, click Microsoft Visual Basic Help on the Help menu, type Const Statement in the Office Assistant or the Answer Wizard, and then click Search to view the topic.