Application.AddUndoUnit method (Visio)
Adds an object that supports the IOleUndoUnit or IVBUndoUnit interface to the Microsoft Visio undo queue.
Syntax
expression.AddUndoUnit (pUndoUnit)
expression A variable that represents an Application object.
Parameters
| Name | Required/Optional | Data type | Description |
|---|---|---|---|
| pUndoUnit | Required | [UNKNOWN] | A reference to an object that supports the IOleUndoUnit or IVBUndoUnit interface. |
Return value
Nothing
Remarks
For information about implementing the IOleUndoUnit interface on your object, see the Microsoft Platform SDK. For information about implementing the IVBUndoUnit interface, see Developing Microsoft Visio Solutions.
Example
The following procedure shows how to use the AddUndoUnit method to add an object to the Visio undo queue. When a shape is added to the active document, the procedure checks to see if it was added as a result of an undo or redo action, and if not, it adds an Undo unit.
This procedure is a member of class clsParticipateInUndo, which is defined in one of two related class modules in the Code Samples Library in the Visio SDK, and is not intended to be run independently. (The other class module defines class clsVBUndoUnits.) For more information about these class modules, see the Visio SDK.
Private Sub mvsoDocument_ShapeAdded(ByVal vsoShape As IVShape)
Dim VBUndoUnit As clsVBUndoUnits
On Error GoTo mvsoDocument_ShapeAdded_Err
If Not (mvsoApplication Is Nothing) Then
If Not msvoApplication.IsUndoingOrRedoing Then
'Increment the count of undoable actions.
IncrementModuleVar
Debug.Print "Original Do: GetModuleVar = " & GetModuleVar
'Instantiate clsVBUndoUnit, a
'class that implements Visio.IVBUndoUnit.
Set VBUndoUnit = New clsVBUndoUnits
'Pass the current instance of the class
'of which this procedure is a member,
'clsParticipateInUndo, to the Undo unit.
VBUndoUnit.SetModelObject Me
'Add an Undo unit.
mvsoApplication.AddUndoUnit VBUndoUnit
End If
End If
Exit Sub
mvsoDocument_ShapeAdded_Err:
MsgBox Err.Description
End Sub
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