When you are automating an Office application from Visual
Basic (VB), the Office application may display a dialog box. The dialog box
causes the Visual Basic application to appear to stop responding (or hang)
because VB is waiting for the dialog box to be dismissed. The dialog box must
be dismissed before the Visual Basic application can continue.
article discusses how you can use the object models for Office applications to
avoid dialog boxes during Automation. It also provides a step-by-step example
of how to simulate user input to programmatically dismiss a dialog box that
cannot be avoided by using the usual properties and methods exposed in the
At times, you may want to automate an Office application
but not require any user interaction with the Office application. In this case,
if the Office application displays a dialog box, your application appears to
stop responding until a user can dismiss the dialog box. However, there may not
be a user sitting in front of the computer who can dismiss the dialog
Office applications were not designed for unattended execution.
Therefore, an application that automates Office may sometimes encounter a
dialog box displayed by the Office application. From normal testing of the
application, you can usually determine which dialog boxes occur and write your
code to avoid those particular dialogs boxes.
Following are some
recommended strategies for avoiding dialog boxes while automating an Office
- Determine if the property or method you are using (the one
that is causing the dialog box) has optional arguments that you can pass to it.
Sometimes, by passing all arguments to the property or method, you can avoid a
dialog box. For example, if you are using the Open method to open an Excel workbook and that workbook is password
protected, Excel displays a dialog box asking the user to enter the password if
you do not provide the password argument when calling the Open method. To avoid the dialog box, provide a value for the Password argument when calling the Open method. Similarly, when using the Close method to close a document, it often helps to specify the SaveChanges argument to avoid a dialog box asking the user to save
For additional information about how to determine what arguments are available for the property or the method that you are calling, click the following article number to view the article in the Microsoft Knowledge Base:
How To Find and use Office object model documentation
- Study the object model of the Office application to see if
there may be a property that prevents certain dialog boxes. For example, the
Excel Application object has AskToUpdateLinks and AlertBeforeOverwriting properties.
- Set the Application.DisplayAlerts property (Excel, Project, Word) or use Application.DoCmd.SetWarnings False (Access only) to turn off the display of alert messages. Most,
but not all, dialog boxes can be avoided using this setting.
- Set the Application.FeatureInstall property (Office 2000 and later) to handle possible "This feature
is not installed..." dialog boxes when accessing a component that may not be
installed on the user's system.
- Use the On Error statement to avoid run-time error messages that could occur, such
as when trying to set the Application.ActivePrinter when no printer driver is installed on the user's system.
- Test your application thoroughly to help anticipate when
dialog boxes may occur. For example, suppose you call the SaveAs method of an Office application to save to a file. If that file
already exists, a dialog box may appear asking confirmation to replace the
existing file. If you modify your code to check for the file before calling the
SaveAs method, you can avoid the possibility of the dialog box
appearing. For example, if the file already exists, delete it using the Kill statement before calling the SaveAs method.
Even if you use these techniques and carefully design your
application to avoid dialog boxes, you may still be faced with a situation
where a dialog box cannot be avoided with the methods and properties exposed in
the Office application's object model. In such situations, it might be
necessary to programmatically dismiss a dialog box by simulating user input.
The following demonstration illustrates how this can be accomplished with a
Visual Basic Automation client.
The steps in this section demonstrate Automation of Microsoft
Word to print a document. The Automation client calls the PrintOut
method for the Word Document
object. If the user's default printer is configured to print to
the FILE port, then a call to PrintOut
produces a dialog box prompting the user to enter a file name. To
determine if the PrintOut
method causes this dialog box to appear, the Visual Basic
Automation client uses a Timer
control to detect idle time after calling the PrintOut
method. Prior to calling PrintOut
, the Timer
is enabled and set to fire in five seconds. When PrintOut
completes, the Timer
is disabled. Therefore, if the PrintOut
method completes within five seconds, the Timer
event never occurs and no further action is taken. The document
is printed and the code execution continues beyond the PrintOut
method. However, if the Timer
event occurs within the five second interval, it is assumed that
method has not completed and that the delay is caused by a dialog
box waiting for user input. When the Timer
event occurs, the Automation client gives focus to Word and uses SendKeys
to dismiss the dialog box. Note
For demonstration purposes, this sample uses the PrintOut
method in such a way that it displays a dialog box intentionally
when it prints to a printer set to a FILE port. Please note that the PrintOut
method has two arguments, OutputfileName
, that you can provide to avoid this dialog box.
Additionally, when using this "timer" approach, you can customize the wait time
to be greater or less than five seconds, as well as customize the keystrokes
you send to the dialog box.
This demonstration consists of two Visual
Create the ActiveX EXE Project
- An ActiveX EXE that provides a Timer class used to detect a
delay. The reason to use an ActiveX EXE for the Timer class is to run the Timer
code in a separate process and, therefore, a separate thread. This makes it
possible for the Timer class to raise an event during a suspended automation
- A Standard EXE that uses automation to Word and calls the PrintOut method to print a document. It uses the ActiveX EXE to detect a
delay when calling the PrintOut method.
Create the Automation Client
- Start Visual Basic and create an ActiveX EXE project.
Class1 is created by default.
- On the Project menu, click to select Properties, and then change the Project name to MyTimer.
- Copy and paste the following code into the Class1 module:
Public Event Timer()
Private oForm1 As Form1
Private Sub Class_Initialize()
Set oForm1 = New Form1
oForm1.Timer1.Enabled = False
Private Sub Class_Terminate()
Me.Enabled = False
Set oForm1 = Nothing
Public Property Get Enabled() As Boolean
Enabled = oForm1.Timer1.Enabled
Public Property Let Enabled(ByVal vNewValue As Boolean)
oForm1.Timer1.Enabled = vNewValue
If vNewValue = True Then
Set oForm1.oClass1 = Me
Set oForm1.oClass1 = Nothing
Public Property Get Interval() As Integer
Interval = oForm1.Timer1.Interval
Public Property Let Interval(ByVal vNewValue As Integer)
oForm1.Timer1.Interval = vNewValue
Friend Sub TimerEvent()
- On the Project menu, choose Add Form to add a new Form to the project.
- Add a Timer control to the form.
- Copy and paste the following code into the code module for
Public oClass1 As Class1
Private Sub Timer1_Timer()
- Save this project in a new subfolder named Server.
- On the File menu, choose Make MyTimer.Exe to build and register the component.
- Create a new Standard EXE project in Visual Basic. Form1 is
created by default.
- Add a CommandButton control to the form.
- On the Project menu, select References. Add references to the Microsoft Word 8.0 (or 9.0, or 10.0) Object Library, and to MyTimer.
- Copy and paste the following code to the form module:
Private oWord As Word.Application
Private strWordCaption As String
Private WithEvents oMyTimer As MyTimer.Class1
Private Sub Form_Load()
'Create MyTimer object, and then disable it by default:
Set oMyTimer = New MyTimer.Class1
oMyTimer.Enabled = False
Private Sub Form_QueryUnload(Cancel As Integer, UnloadMode As Integer)
'Terminate MyTimer object when the form is closed:
oMyTimer.Enabled = False
Set oMyTimer = Nothing
Private Sub Command1_Click()
On Error GoTo ErrorHandler
'Create a new Word instance and put text in the new document:
Set oWord = CreateObject("Word.Application")
oWord.Visible = True
oWord.Selection.TypeText "Hello World!"
'Prepare Timer to "watch out" for a delay in calling PrintOut:
strWordCaption = GetWordCaption 'for use with AppActivate
oMyTimer.Interval = 5000 'allow 5 second wait time
oMyTimer.Enabled = True
'Call the PrintOut method, which may prompt the user to select
'an output file name if the default printer is set to FILE:
On Error Resume Next
'Turn off Timer:
oMyTimer.Enabled = False
'Close document and quit the Word instance:
Set oWord = Nothing
Private Sub oMyTimer_Timer()
'If this event occurs, there was a delay in calling PrintOut.
'You can assume that the delay is caused by a dialog box prompting
'for an output file name because the user has the printer
'configured to print to FILE. SendKeys is used to provide the
'output file name and dismiss the dialog box.
Dim strKeys As String
On Error Resume Next
'Make sure that Word has the focus before using SendKeys to it:
AppActivate strWordCaption 'Set focus to Word.
'Send keystrokes to enter the output file name:
If Right$(App.Path, 1) = "\" Then
strKeys = App.Path & "MyOutput.prn"
strKeys = App.Path & "\MyOutput.prn"
Kill strKeys 'make sure file does not already exist
strKeys = strKeys & "~" '~ represents the OK button to dismiss dialog
SendKeys strKeys, True
oMyTimer.Enabled = False
Private Function GetWordCaption() As String
'Returns the Word Caption. For use with the AppActivate statement
Dim s As String
On Error Resume Next
If Left$(oWord.Version, 1) = "8" Then
'Word 97 logic:
s = oWord.Caption
'Word 2000 or 2002 logic:
s = oWord.ActiveWindow.Caption
If Err.Number = 0 Then 'no error
s = s & " - " & oWord.Caption
s = oWord.Caption
GetWordCaption = s
- Save this project in a new subfolder named Client.
- Press the F5 key to run the project. Form1 appears.
- Click Command1 on the form. This automates Word, adds a new document with some
text, and then sends it to the printer by using the PrintOut method. You do not see a dialog box if your printer is configured
to print to a printer.
- In the Windows Control Panel, change your default printer
so that it is configured to print to the FILE port.
- Click Command1 again,and note that a dialog box appears in Word. Do not dismiss
the dialog; wait five seconds and the dialog box is programmatically dismissed
when the Timer event occurs. An output file named MyOutput.prn is created in the
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 a Microsoft Certified Partner or Microsoft Advisory Services. For more information, visit these Microsoft Web sites:
Microsoft Certified Partners - https://partner.microsoft.com/global/30000104
Microsoft Advisory Services - http://support.microsoft.com/gp/advisoryservice
For more information about the support options that are available and about how to contact Microsoft, visit the following Microsoft Web site:http://support.microsoft.com/default.aspx?scid=fh;EN-US;CNTACTMS
For additional information, click the following article numbers to view the articles in the Microsoft Knowledge Base:
INFO: Considerations for server-side automation of Office
OFF2000: Programming resources for Visual Basic for Applications
FILE: Offautmn.exe discusses Office 97 and 2000 automation and provides sample code
For additional information about Office automation, visit the Office Development Support Center at the following Microsoft Web site:
Article ID: 259971 - Last Review: January 17, 2007 - Revision: 6.7
- Microsoft Office Access 2003
- Microsoft Access 2002 Standard Edition
- Microsoft Access 2000 Standard Edition
- Microsoft Access 97 Standard Edition
- Microsoft Office Excel 2003
- Microsoft Excel 2002 Standard Edition
- Microsoft Excel 2000 Standard Edition
- Microsoft Excel 97 Standard Edition
- Microsoft Office PowerPoint 2003
- Microsoft PowerPoint 2002 Standard Edition
- Microsoft PowerPoint 2000 Standard Edition
- Microsoft PowerPoint 97 Standard Edition
- Microsoft Office Word 2003
- Microsoft Word 2002
- Microsoft Word 2000
- Microsoft Word 97 Standard Edition
- Microsoft Visual Basic 5.0 Professional Edition
- Microsoft Visual Basic 6.0 Professional Edition
- Microsoft Visual Basic 5.0 Enterprise Edition
- Microsoft Visual Basic Enterprise Edition for Windows 6.0
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