How to obtain the window handle for an Office Automation server by using Visual Basic .NET (302281)
The information in this article applies to:
- Microsoft Visual Basic .NET (2003)
- Microsoft Visual Basic .NET (2002)
- Microsoft Office Access 2003
- Microsoft Access 2002
- Microsoft Office Excel 2003
- Microsoft Excel 2002
- Microsoft Office PowerPoint 2003
- Microsoft PowerPoint 2002
- Microsoft Office Word 2003
- Microsoft Word 2002
This article was previously published under Q302281 SUMMARY This article demonstrates how to obtain the window handle
of a Microsoft Office application while automating that application from Microsoft Visual
Basic .NET. MORE INFORMATION The object models for most Office applications do not
expose properties for retrieving the application window handles. To determine
the window handle of an Office application that you are automating, you can use
the FindWindow function with the class name of the topmost window for the
application. If the application can have multiple instances running at the same
time, you may need to account for this so that you retrieve the correct window
handle. The following sections illustrate techniques for retrieving the window
handle for both single and multiple instance applications. Note The Microsoft Access object model exposes the hWndAccessApp property for the Application object for determining the window handle of the application. You
can also use the hWnd property for Forms and Reports to retrieve handles to those
specific windows. Additionally, Microsoft Excel 2002 is the first version of Excel to
introduce an hWnd property for its Application object. Regarding Excel 2002 and later and Microsoft Access
97 and later, the FindWindow approach that is discussed in this article is not necessary because these Office applications can retrieve the window handle for the
application through their respective object models. Find the window handle for an application that is a single instance The following steps illustrate how you can use the FindWindow function with a Visual Basic Automation client to determine
the window handle for an out-of-process Automation server that can have only a
single instance. This is the technique that you employ when you use Microsoft PowerPoint
as your Automation server. Step-by-step example- Start Microsoft Visual Studio .NET.
- On the File menu, click New, and then click Project. Select Windows Application from the list of Visual Basic Projects types. Form1 is created by
default.
- Add a reference to the Microsoft PowerPoint Object Library. To do this, follow these steps:
- On the Project menu, click Add Reference.
- On the COM tab, locate the Microsoft PowerPoint Object Library, and then click Select.
Note Microsoft Office 2003 includes Primary Interop Assemblies (PIAs). Microsoft Office
XP does not include PIAs, but they may be downloaded.
For more information about Office XP PIAs, click the following article number to view the article in the Microsoft Knowledge Base:
328912
Microsoft Office XP primary interop assemblies (PIAs) are available for download
- Click OK in the Add References dialog box to accept your selections. If you are prompted to
generate wrappers for the libraries that you selected, click Yes.
- On the View menu, select Toolbox to display the Toolbox, and then add a button to the form.
- Press F7 to view the code window for Form1.
- Paste the following code at the beginning of the code
window:
Imports System.Runtime.InteropServices
Imports Microsoft.Office.Interop
Public Class MyApi
<DllImport("user32.dll")> Public Shared Function _
FindWindow(ByVal strClassName As String, ByVal strWindowName _
As String) As Integer
End Function
End Class
- Add the following code to the Click event of Button1:
Dim pptApp As PowerPoint.Application
Dim hwndPPt As Integer
pptApp = New PowerPoint.Application()
pptApp.Visible = True
hwndPPt = MyApi.FindWindow("PP10FrameClass", Nothing)
MsgBox("hwndPPt (" & Hex(hwndPPt) & ") has the Window handle to " & _
"Powerpoint's Main Window." & vbCr & " Click OK to close PowerPoint.")
pptApp.Quit()
NotePP10FrameClass is the class name for the Microsoft PowerPoint 2002
application window. If you automate
PowerPoint 2003, change the class name in the code to
PP11FrameClass. - Press F5 and click Button1 to run the sample.
Find the window handle for an application that can have multiple instances Some applications, such as Microsoft Excel or Microsoft Word, can have multiple
instances running at the same time. To retrieve the handle to the application
instance that you are automating, you can first use Automation to change the
title of the application to a unique value and then use the FindWindow function to retrieve its window handle. The following steps
illustrate this technique by using Excel as the Automation server. Step-by-step example- Start Visual Studio .NET.
- On the File menu, click New, and then click Project. Select Windows Application from the Visual Basic Projects types. Form1 is created by default.
- Add a reference to the Microsoft Excel Object Library. To do this, follow these steps:
- On the Project menu, click Add Reference.
- On the COM tab, locate the Microsoft Excel Object Library, and then click Select.
Note Microsoft Office 2003 includes Primary Interop Assemblies (PIAs). Microsoft Office
2002 does not include PIAs, but they may be downloaded.
For more information about Office XP PIAs, click the following article number to view the article in the Microsoft Knowledge Base:
328912
Microsoft Office XP primary interop assemblies (PIAs) are available for download
- Click OK in the Add References dialog box to accept your selections. If you are prompted to
generate wrappers for the libraries that you selected, click Yes.
- On the View menu, select Toolbox to display the Toolbox, and then add a button to the form.
- Press F7 to view the code window for Form1.
- Paste the following code at the beginning of the code
window:
Imports System.Runtime.InteropServices
Imports Microsoft.Office.Interop
Public Class MyApi
<DllImport("user32.dll")> Public Shared Function _
FindWindow(ByVal strClassName As String, ByVal strWindowName _
As String) As Integer
End Function
End Class
- Add the following code to the Click event of Button1:
Dim xlapp As Excel.Application
Dim hwndExcel As Integer
xlapp = New Excel.Application()
xlapp.Visible = True
xlapp.Caption = "Some Window Caption"
hwndExcel = MyApi.FindWindow("XLMAIN", xlapp.Caption)
xlapp.Caption = Nothing
MsgBox("hwndExcel (" & Hex(hwndExcel) & ") has the Window handle to " & _
"Excel's Main Window." & vbCr & " Click OK to close Excel." )
xlapp.Quit()
- Press F5 and click Button1 to run the sample.
REFERENCES For more information, visit the following Microsoft Developer
Network (MSDN) Web site:
For more information about retrieving the window handle for an Office Automation server by using earlier versions of Visual Basic, click the following article number to view the article in the Microsoft Knowledge Base:
258511
How to obtain the window handle for an Office Automation server
Modification Type: | Major | Last Reviewed: | 11/2/2005 |
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Keywords: | kbAutomation kbhowto KB302281 |
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