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                    Microsoft Office Application Development

Catching Paste Operations

Introduction

You know the situation: You have carefully setup a workbook with intricate Validation schemes. But then along comes your user and he copies and pastes at will. Result: Validation zapped, workbook structure violated.

What to do? The only way I find reliable is to catch all possible paste operations. But this isn't very easy, since there are a zilion ways to paste:

This article shows one way to intercept all these paste operations.

NB: as it is now, the article focuses on Excel 2000 to 2003. I will add the needed steps for Excel 2007 later on.

Explanation Of Parts Of The Code

Catching Keyboard Shortcuts

The only way to catch paste keyboard shortcuts is by assigning them to your own paste code. E.g. like this:

    Application.OnKey "^v", "MyPasteValues"
    Application.OnKey "^{Insert}", "MyPasteValues"
    Application.OnKey "+{Insert}", "MyPasteValues"
    Application.OnKey "~", "MyPasteValues"
    Application.OnKey "{Enter}", "MyPasteValues"

(the MyPasteValues routine is shown further below)

Catching Clicks On Toolbar And Menu Controls

To catch clicks on Commandbar controls, I used a class module in which a variable is declared of type commandbarcontrol, using the WithEvents keyword. Then an instance of this class module is created for each control I want to intercept.

The class (named clsCommandBarCatcher), contains this code:

'-------------------------------------------------------------------------
' Module    : clsCommandBarCatcher
' Company   : JKP Application Development Services (c)
' Author    : Jan Karel Pieterse
' Created   : 4-10-2007
' Purpose   : This class catches clicks on Excel's commandbars to be able to prevent pasting.
'-------------------------------------------------------------------------
Option Explicit

Public WithEvents oComBarCtl As Office.CommandBarButton

Private Sub Class_Terminate()
    Set oComBarCtl = Nothing
End Sub

Private Sub oComBarCtl_Click(ByVal Ctrl As Office.CommandBarButton, CancelDefault As Boolean)
    CancelDefault = True
    Application.OnTime Now, "MyPasteValues"
End Sub

And the code to create an instance of this class could look like this:

    Dim oCtl As CommandBarButton
    Dim CCatcher As clsCommandBarCatcher
    Set oCtl = Application.CommandBars("Cells").FindControl(ID:=3185, recursive:=True)
    Set CCatcher = New clsCommandBarCatcher
    Set CCatcher.oComBarCtl = oCtl

To keep the instances of the classes "alive" I create a (module) collection variable and add each instance to the collection.

The paste is handled by this routine:

Public Sub MyPasteValues()
'-------------------------------------------------------------------------
' Procedure : EnableDisableControl
' Author    : Jan Karel Pieterse www.jkp-ads.com
' Created   : 24-9-2007
' Purpose   : Propriatary paste values routine called from control event
'             handler in clsCommandBarCatcher and from various OnKey macros.
'-------------------------------------------------------------------------
    If Application.CutCopyMode <> False Then
        If MsgBox("Normal paste operation has been disabled. You are about to Paste Values (cannot be undone), proceed?" & vbNewLine & "Tip: to be able to undo a paste, use the paste values button on the toolbar.", vbQuestion + vbOKCancel, _
            "CatchPaste Demo") = vbOK Then
            On Error Resume Next
            Selection.PasteSpecial Paste:=xlValues
            IsCellValidationOK Selection
        End If
    ElseIf Application.MoveAfterReturn Then
        On Error Resume Next
        Select Case Application.MoveAfterReturnDirection
        Case xlUp
            ActiveCell.Offset(-1).Select
        Case xlDown
            ActiveCell.Offset(1).Select
        Case xlToRight
            ActiveCell.Offset(, 1).Select
        Case xlToLeft
            ActiveCell.Offset(, -1).Select
        End Select
    End If
End Sub

Note that the code above also mimicks the MoveAfterReturn behaviour of Excel.

Cell Drag And Drop Mode

Dragging the fill handle is another way to wreck your validation. Hence this is turned off too. Unfortunately changing this setting empties the clipboard, so this setting cannot be toggled at will when switching workbooks. If you do turn it on and off when switching to and from your workbook, copying and pasting from another workbook to the one with the code becomes impossible.

Validation

The code I showed above redirects all paste operations to one routine, which does a paste special, values. But pasting does not trigger any validation checks. Also, there is no way of knowing what cells may be affected by the paste before the actual paste has been done. Luckily, after the paste, the Selection object is equal to the cells affected by the paste. Using the "Validation" object of the Range object it is possible to check whether the cells adhere to their validation settings. I created this function, to which I pass the range that has been changed. The function returns False as soon as any cell violates its validation rule:

Public Function IsCellValidationOK(oRange As Object) As Boolean
'-------------------------------------------------------------------------
' Procedure : ValidateCells
' Author    : Jan Karel Pieterse www.jkp-ads.com
' Created   : 21-11-2007
' Purpose   : This routine checks if entries pasted into the cells in oRange
'             are not violating a validation rule.
'             Returns False if any cell's validation is violated
'-------------------------------------------------------------------------
    Dim oCell As Range
    If TypeName(oRange) <> "Range" Then Exit Function
    IsCellValidationOK = True
    For Each oCell In oRange
        If Not oCell.Validation Is Nothing Then
            If oCell.HasFormula Then
            Else
                If oCell.Validation.Value = False Then
                    IsCellValidationOK = False
                    Exit For
                End If
            End If
        End If
    Next
    If IsCellValidationOK = False Then
        MsgBox "Warning!!!" & vbNewLine & vbNewLine & _
            "The paste operation has caused illegal entries to appear" & vbNewLine & _
            "in one or more cells containing validation rules." & vbNewLine & vbNewLine & _
            "Please check all cells you have just pasted " & vbNewLine & _
            "into and correct any errors!", vbOKOnly + vbExclamation, _
            "CatchPaste Demo"
        oRange.Select
    End If
End Function

Switching On And Off

Of course I want this paste restriction to work on just the workbook with the code. This means some code in the ThisWorkbook module is needed, to be precise in the Workbook_DeActivate and Workbook_Activate events. This is all code I have in ThisWorkbook:

 Option Explicit

'Holds time of scheduled ontime macro
'(Workbook_Before_Close and Workbook_Deactivate)
Private mdNextTimeCatchPaste As Double

Private Sub Workbook_Activate()
    CatchPaste
End Sub

Private Sub Workbook_BeforeClose(Cancel As Boolean)
    StopCatchPaste
    mdNextTimeCatchPaste = Now
    'Schedule a macro to reinstate the catch in case closing is cancelled
    Application.OnTime mdNextTimeCatchPaste, "'" & ThisWorkbook.Name & "'!CatchPaste"
    Application.CellDragAndDrop = True
End Sub

Private Sub Workbook_Deactivate()
    StopCatchPaste
    On Error Resume Next
    'Cancel scheduled macro's,
    'because we seem to be closing the file
    Application.OnTime mdNextTimeCatchPaste, "'" & ThisWorkbook.Name & "'!CatchPaste", , False
End Sub

Private Sub Workbook_Open()
    CatchPaste
End Sub

Putting It All Together

The entire module that handles the initialisation and processes the paste operation looks like this:

'-------------------------------------------------------------------------
' Module    : modHandlePaste
' Author    : Jan Karel Pieterse
' Created   : 24-9-2007
' Purpose   : Module that ensures paste and paste formats is disabled
'-------------------------------------------------------------------------
Option Explicit
Option Private Module

Dim mcCatchers As Collection

Sub CatchPaste()
'-------------------------------------------------------------------------
' Procedure : CatchPaste
' Author    : Jan Karel Pieterse www.jkp-ads.com
' Created   : 24-9-2007
' Purpose   : This routine ensures all paste operations are redirected to our own.
'             This way we avoid overwriting styles and validations.
'-------------------------------------------------------------------------
    StopCatchPaste
    Set mcCatchers = New Collection
    'Paste button
    AddCatch "Dummy", 22
    'Paste button (with dropdown)
    EnableDisableControl 6002, False
    'Paste Special button
    AddCatch "Dummy", 755
    'Paste As Hyperlink button
    AddCatch "Dummy", 2787
    'Paste Formats bottun
    AddCatch "Dummy", 369
    'Insert Cut cells button
    AddCatch "Dummy", 3185
    'Insert Copied Cells button
    AddCatch "Dummy", 3187
    Application.OnKey "^v", "MyPasteValues"
    Application.OnKey "^{Insert}", "MyPasteValues"
    Application.OnKey "+{Insert}", "MyPasteValues"
    Application.OnKey "~", "MyPasteValues"
    Application.OnKey "{Enter}", "MyPasteValues"
    
    'Changing the celldragdrop mode clears the clipboard.
    'This means if you switch from another workbook back to this one, you would be unable to copy
    'information and paste it into the template. This is why we do not reinstate the
    'celldragdropmode when switching away from a B1 template and vice versa: switch it off
    'when we return to a template.
    If Application.CellDragAndDrop Then
        'If the user has manually changed this mode to true, the clipboard WILL be emptied due to the next line
        Application.CellDragAndDrop = False
    End If
End Sub

Sub StopCatchPaste()
'-------------------------------------------------------------------------
' Procedure : StopCatchPaste
' Author    : Jan Karel Pieterse www.jkp-ads.com
' Created   : 24-9-2007
' Purpose   : Resets the paste operations to their defaults
'-------------------------------------------------------------------------

    Dim lCount As Long
    On Error Resume Next
    Set mcCatchers = Nothing
    EnableDisableControl 6002, True
    Application.OnKey "^v"
    Application.OnKey "^{Insert}"
    Application.OnKey "+{Insert}"
    Application.OnKey "~"
    Application.OnKey "{Enter}"
    'Changing the celldragdrop mode clears the clipboard.
    'This means if you switch from another workbook back to this one, you would be unable to copy
    'information and paste it into the template. This is why we do not reinstate the
    'celldragdropmode when switching away from a B1 template and vice versa: switch it off
    'when we return to a template.
    'Next line disabled for this reason!!!
'    Application.CellDragAndDrop = True
End Sub

Sub AddCatch(sCombarName As String, lID As Long)
'-------------------------------------------------------------------------
' Procedure : AddCatch
' Author    : Jan Karel Pieterse www.jkp-ads.com
' Created   : 24-9-2007
' Purpose   : Adds a commandbarcontrol to be monitored
'-------------------------------------------------------------------------
    Dim oCtl As CommandBarControl
    Dim cCatcher As clsCommandBarCatcher
    Dim oBar As CommandBar
    Set oCtl = Nothing
    On Error Resume Next
    Set oBar = Application.CommandBars(sCombarName)
    If oBar Is Nothing Then
        Set oBar = Application.CommandBars.Add(sCombarName, , , True)
        oBar.Controls.Add ID:=lID
        oBar.Visible = True
    End If
    With oBar
        Set oCtl = .FindControl(ID:=lID, recursive:=True)
        If oCtl Is Nothing Then
            Set oCtl = .Controls.Add(ID:=lID)
        End If
    End With
    'Try Insert copied/cut cells separately through the cells shortcut menu
    If oCtl Is Nothing And (lID = 3185 Or lID = 3187) Then
        Set oCtl = Application.CommandBars("Cell").FindControl(ID:=lID, recursive:=True)
    End If
    Set cCatcher = New clsCommandBarCatcher
    Set cCatcher.oComBarCtl = oCtl
    mcCatchers.Add cCatcher
    Set cCatcher = Nothing
    oBar.Delete
    Set oBar = Nothing
End Sub

Private Sub EnableDisableControl(lID As Long, bEnable As Boolean)
'-------------------------------------------------------------------------
' Procedure : EnableDisableControl
' Author    : Jan Karel Pieterse www.jkp-ads.com
' Created   : 24-9-2007
' Purpose   : Enables or disables a specific control on all commandbars
'-------------------------------------------------------------------------

    Dim oBar As CommandBar
    Dim oCtl As CommandBarControl
    On Error Resume Next
    For Each oBar In CommandBars
        Set oCtl = oBar.FindControl(ID:=lID, recursive:=True)
        If Not oCtl Is Nothing Then
            oCtl.Enabled = bEnable
        End If
    Next
End Sub

Public Sub MyPasteValues()
'-------------------------------------------------------------------------
' Procedure : EnableDisableControl
' Author    : Jan Karel Pieterse www.jkp-ads.com
' Created   : 24-9-2007
' Purpose   : Propriatary paste values routine called from control event
'             handler in clsCommandBarCatcher and from various OnKey macros.
'-------------------------------------------------------------------------
    If Application.CutCopyMode <> False Then
        If MsgBox("Normal paste operation has been disabled. You are about to Paste Values (cannot be undone), proceed?" & vbNewLine & "Tip: to be able to undo a paste, use the paste values button on the toolbar.", vbQuestion + vbOKCancel, _
            "CatchPaste Demo") = vbOK Then
            On Error Resume Next
            Selection.PasteSpecial Paste:=xlValues
            IsCellValidationOK Selection
        End If
    ElseIf Application.MoveAfterReturn Then
        On Error Resume Next
        Select Case Application.MoveAfterReturnDirection
        Case xlUp
            ActiveCell.Offset(-1).Select
        Case xlDown
            ActiveCell.Offset(1).Select
        Case xlToRight
            ActiveCell.Offset(, 1).Select
        Case xlToLeft
            ActiveCell.Offset(, -1).Select
        End Select
    End If
End Sub

Public Function IsCellValidationOK(oRange As Object) As Boolean
'-------------------------------------------------------------------------
' Procedure : ValidateCells
' Author    : Jan Karel Pieterse www.jkp-ads.com
' Created   : 21-11-2007
' Purpose   : This routine checks if entries pasted into the cells in oRange
'             are not violating a validation rule.
'             Returns False if any cell's validation is violated
'-------------------------------------------------------------------------
    Dim oCell As Range
    If TypeName(oRange) <> "Range" Then Exit Function
    IsCellValidationOK = True
    For Each oCell In oRange
        If Not oCell.Validation Is Nothing Then
            If oCell.HasFormula Then
            Else
                If oCell.Validation.Value = False Then
                    IsCellValidationOK = False
                    Exit For
                End If
            End If
        End If
    Next
    If IsCellValidationOK = False Then
        MsgBox "Warning!!!" & vbNewLine & vbNewLine & _
            "The paste operation has caused illegal entries to appear" & vbNewLine & _
            "in one or more cells containing validation rules." & vbNewLine & vbNewLine & _
            "Please check all cells you have just pasted " & vbNewLine & _
            "into and correct any errors!", vbOKOnly + vbExclamation, _
            "CatchPaste Demo"
        oRange.Select
    End If
End Function

Sample File

I prepared a sample file so you can see how to put this all together.

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