ID: Q152261
The information in this article applies to:
SUMMARY
This article demonstrates a method for using application programming interface (API) calls in a multiplatform macro.
When you use Windows API functions from a Visual Basic for Applications macro, you may need to account for the bitness (32-bit or 16-bit) of the macro environment. You will need to make the API declarations for both the 32-bit and the 16-bit versions and selectively call the appropriate library according to your current macro environment.
The recommended method for calling API functions from within Visual Basic for Applications is to encapsulate the API function in a Visual Basic for Applications function. The Visual Basic for Applications function would then be used in the main code routines.
The following example shows this methodology applied to a macro example that will activate a window, given its Class name. For additional information, please see the following article in the Microsoft Knowledge Base:
ARTICLE-ID: Q104710
TITLE : INF: How to Activate an Application with Class Name (2.0)
Microsoft provides programming examples for illustration only, without warranty either expressed or implied, including, but not limited to, the implied warranties of merchantability and/or fitness for a particular purpose. This article assumes that you are familiar with the programming language being demonstrated and the tools used to create and debug procedures. Microsoft support professionals can help explain the functionality of a particular procedure, but they will not modify these examples to provide added functionality or construct procedures to meet your specific needs. If you have limited programming experience, you may want to contact the Microsoft fee-based consulting line at (800) 936-5200. For more information about the support options available from Microsoft, please see the following page on the World Wide Web:
http://www.microsoft.com/support/supportnet/refguide/
NOTE: In the following sample code, an underscore (_) is used as a line-
continuation character. Remove the underscore from the end of the
line for the following declare statements. Declares must be entered on a
single line.
' 32 Bit Declares.
Declare Function ShowWindow32 Lib "user32" Alias "ShowWindow" _
(ByVal hwnd As Long, ByVal nCmdShow As Long) As Long
Declare Function FindWindow32 Lib "user32" Alias "FindWindowA" _
(ByVal lpClassName As String, ByVal lpWindowName As String) As Long
Declare Function SetForegroundWindow32 Lib "user32" Alias _
"SetForegroundWindow" (ByVal hwnd As Long) As Long
' 16 Bit Declares.
Declare Function ShowWindow Lib "User" (ByVal hwnd As Integer, _
ByVal nCmdShow As Integer) As Integer
Declare Function SetActiveWindow Lib "User" (ByVal hwnd As _
Integer) As Integer
Declare Function FindWindow Lib "User" (ByVal lpClassName As _
Any, ByVal lpWindowName As Any) As Integer
' Test routine. Run this subroutine.
Sub TestIt_ActivateAppClass()
Dim strClassName As String
Dim iRetVal As Integer
strClassName = "opusapp"
iRetVal = AppActivateClass(strClassName)
If Not iRetVal Then MsgBox strClassName & " Is NOT currently " & _
"running"
End Sub
' VB Api encapsulation function for ShowWindow.
Function vb_ShowWindow(ByVal hwnd As Long)
Const SW_SHOW = 9
If is32Bit Then
iRetVal = SetForegroundWindow32(hwnd)
iRetVal = ShowWindow32(hwnd, SW_SHOW)
Else
iRetVal = SetActiveWindow(hwnd)
iRetVal = ShowWindow(hwnd, SW_SHOW)
End If
vb_ShowWindow = iRetVal
End Function
' VB Api encapsulation function for FindWindow.
Function vb_FindWindow(ByVal lpClassName As String) As Long
Dim strNullString As String 'Define Null String Variable
If is32Bit Then
vb_FindWindow = FindWindow32(lpClassName, strNullString)
Else
vb_FindWindow = FindWindow(lpClassName, 0&)
End If
End Function
Function is32Bit() As Boolean
is32Bit = False ' Assume Failure.
If InStr(1, Application.OperatingSystem, "32", 1) > 1 Then
is32Bit = True
End If
End Function
Function AppActivateClass(lpClassName As String) As Boolean
Dim hwnd As Long ' The application's window handle.
Dim iRetVal As Integer ' Temp variable.
Dim iCmdShow As Integer ' The ShowWindow cmdshow argument.
ActivateAppClass = False ' Assume Failure.
hwnd = vb_FindWindow(lpClassName) ' Get the Window Handle for
' the className.
If hwnd <> 0 Then ' The class was found.
iRetVal = vb_ShowWindow(hwnd) ' Activate the Application.
ActivateAppClass = True ' Return True if Application
' Running.
End If
End Function
"TestIt_ActivateAppClass" (without the quotation marks), and click Run.
Keywords : kbprg kbdta kbdtacode KbVBA kbhowto
Version : WINDOWS:5.0,5.0c,7.0,7.0a,97
Platform : WINDOWSLast Reviewed: May 18, 1999