Using BeforeUpdate to format textbox, Excel not showing updated

[vaxman9]

Greetings all,

I have a UserForm I am using for data input with an XLS file. I have a textbox that I am using for phone number entry that has a cell in the XLS sheet as the control source. In the BeforeUpdate method, I call a function that does a check for 7 or 10 digits and if the check clears, returns a formatted value:

Private Sub txtC1_Phone_BeforeUpdate(ByVal cancel As MSForms.ReturnBoolean)
    txtC1_Phone = Check_Phone(Me.txtC1_Phone, cancel, "Contact #1 Phone Number")
End Sub

Public Function Check_Phone(objContl As Object, ByVal Cancel As MSForms.ReturnBoolean, strText As String)
   Dim varWkr As Variant, i As Integer
    varWrk = Replace(objContl, "(", "")
    varWrk = Replace(varWrk, ")", "")
    varWrk = Replace(varWrk, "-", "")
    varWrk = Replace(varWrk, " ", "")

    Select Case Len(varWrk)
    Case Is = 0
       '
       '   Empty
       '
    Case Is = 7
       Check_Phone = Format("   " & varWrk, "###-####")    
    Case Is = 10
       Check_Phone = Format(varWrk, "(###) ###-####")
    Case Else
       Check_Phone = objContl
       Cancel = True
        MsgBox "The " & strText & _
	" you've entered does not seem complete, Please Check", _
                vbInformation + vbOKOnly, "Please Check" 
    End Select
End Function

After the BeforeUpdate, the textbox is showing the correct format, but the cell in the XLS sheet is showing the "Non-formatted" value.
For example:
I type "1234567890" in the textbox in my UserForm and hit enter. The cell in the XLS sheet shows "1234567890", but the Textbox is showing "(123) 456-7890". It seems the control source is being updated with the value of the textbox prior the the BeforeUpdate event fires. If the event results in a Cancel=True, the orginal value is restored.

Any insights would be greatly appreciated.
Thank you,
msc