<Resolved> How to stop error message if cancel pressed

[Borg2of6]

I am using the code below to validate the entry in a text field:

Private Sub txtHomeNotes_Exit(ByVal Cancel As MSForms.ReturnBoolean)
Dim RespMsg
If Len(txtHomeNotes.Value) > 150 Then
RespMsg = MsgBox("Notes must not be more than 150 characters in length." & Chr(10) & "Please compress message", vbExclamation + vbOKOnly, "Notes Error")
txtHomeNotes.SetFocus
End If
End Sub

If the user has entered 151 or more characters in the notes box and then presses the cancel command button, the MsgBox is still displayed. Is there any way to detect that the Cancel command button has been pressed, therefore allowing me to supress the error message.

I would prefer all validation to be done on exit from text box rather than upon pressing the OK command button, as I am using validation for several other text boxes as well. They all give the same problem.

I am using VBA for Excel.