Document.BeginUndoScope Method

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Visio Automation Reference

Starts a transaction with a unique scope ID for an instance of Microsoft Office Visio.

Version Information
 Version Added:  Visio 2000

Syntax

expression.BeginUndoScope(bstrUndoScopeName)

expression   A variable that represents a Document object.

Parameters

Name Required/Optional Data Type Description
bstrUndoScopeName Required String The name of the scope; could appear in the Visio user interface.

Return Value
Long

Remarks

If you need to know whether events you receive are the result of a particular operation that you initiated, use the BeginUndoScope and EndUndoScope methods to wrap your operation. In your event handlers, use the IsInScope property to test whether the scope ID returned by the BeginUndoScope method is part of the current context. Make sure you clear the scope ID you stored from the BeginUndoScope property when you receive the ExitScope event with that ID.

You must balance calls to the BeginUndoScope method with calls to the EndUndoScope method. If you call the BeginUndoScope method, you should call the EndUndoScope method as soon as you are finished with the actions that constitute your scope. Also, while actions to multiple documents should be robust within a single scope, closing a document may have the side effect of clearing the undo information for the currently open scope as well as clearing the undo and redo stacks. If that happens, passing bCommit = False to EndUndoScope does not restore the undo information.

You can also use the BeginUndoScope and EndUndoScope methods to add an action defined by an add-on to the Visio undo stream. This is useful when you are operating from modeless scenarios where the initiating agent is part of an add-on's user interface or a modeless programmatic action.

ms426696.vs_note(en-us,office.12).gif  Note
Most Visio actions are already wrapped in internal undo scopes, so add-ons running within the application do not need to call this method.

Example

This example shows how to use the BeginUndoScope method to start a transaction that has a unique scope ID for an instance of Visio.

Visual Basic for Applications 
  
Private WithEvents vsoApplication As Visio.Application 
Private lngScopeID As Long

Public Sub BeginUndoScope_Example()


Dim vsoShape As Visio.Shape 

'Set the module-level application variable to 
'trap application-level events. 
Set vsoApplication = Application 

'Begin a scope and set the module-level scope ID variable. 
lngScopeID = Application.BeginUndoScope("Draw Shapes") 

'Draw three shapes. 
Set vsoShape = ActivePage.DrawRectangle(1, 2, 2, 1) 
ActivePage.DrawOval 3, 4, 4, 3 
ActivePage.DrawLine 4, 5, 5, 4 

'Change a cell to trigger the CellChanged event. 
vsoShape.Cells("Width").Formula = 5 

'End and commit this scope. 
Application.EndUndoScope lngScopeID, True



End Sub


Private Sub vsoApplication_CellChanged(ByVal Cell As IVCell)


'Check to see if this cell change is the result of something 
'happening within the scope. 
If vsoApplication.IsInScope(lngScopeID) Then 
    Debug.Print Cell.Name & " changed in scope "; lngScopeID 
End If  



End Sub


Private Sub vsoApplication_EnterScope(ByVal app As IVApplication, _
ByVal nScopeID As Long, _
ByVal bstrDescription As String)


If vsoApplication.CurrentScope = lngScopeID Then 
    Debug.Print "Entering my scope " & nScopeID 
Else 
    Debug.Print "Enter Scope " & bstrDescription & "(" & nScopeID & ")" 
End If 



End Sub


Private Sub vsoApplication_ExitScope(ByVal app As IVApplication, _
ByVal nScopeID As Long, _
ByVal bstrDescription As String, _
ByVal bErrOrCancelled As Boolean)


If vsoApplication.CurrentScope = lngScopeID Then 
    Debug.Print "Exiting my scope " & nScopeID 
Else 
    Debug.Print "Exit Scope " & bstrDescription & "(" & nScopeID & ")" 
End If  



End Sub

See Also