UCase & Cancel

Greetings all,
I am hoping that someone here can provide a solution to an odd problem that I have run into with my project. I am using Access 2016 working on a single form. The form has four inputs and three buttons. Two of these are at the core of my issue.
I have a text field, txtref, which I use to enter manual references into. I have code that converts any letters to capitals.

Code:

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Private Sub txtref_LostFocus()


Dim t As String  'Raw inital string input from user.
Dim e As String  'Final output


If Not IsNull(t) Then
    t = Me.txtref.Value
    e = UCase(t) 'UCase forces any leters to be captilaized.
    Me.txtref.Value = e
End If


End Sub

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I am using a command button, cmdCancel, to abort an entry before it is saved.

Code:

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Private Sub cmdCancel_Click()


Me.Undo
DoCmd.Close , , acSaveNo


End Sub

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The form has a description field which is auto populated from a previous form. (this function works perfectly) I have a combo box for publisher, and a combo box for reference type. Both of these work just fine. The cancel button is throwing me for a loop. When the form opens, if I click cancel, the form closes without any records being created. If I enter a response into the publisher combo box and click cancel, the form closes without any records being created. However if I enter responses into publisher and reference type combo boxes and tab into the reference number text box and click cancel I get an error for "Invalid Use of Null". I tried changing the code to a Len (t) > 0 Then, and this worked, however the UCase function stopped working. I tried using a message box and If and Else statements to determine if it was just me missing something. One message was for an empty text field and the other was for anything being entered into the text field. What I found is that no matter what I do, as soon as the txtref box has the cursor it think that there is text there. I know I'm close, but I can't seem to put my finger on what it is that I am missing to make the cancel function work at any time.

Any help is appreciated. Thanks in advance.
While testing the buttons on my form today I noted something interesting.

Code:

---

Private Sub txtref_LostFocus()

  .Value = UCase(.Value) ' If Value is null then UCase(Value) returns Null
End Sub

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:dunno: but try

Code:

---

Private Sub cmdCancel_Click()

Me.UndoAction
DoCmd.Close , , acSaveNo
End Sub

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Well I'm feeling slightly relieved and a little silly. :beerchug: Thanks for the suggestion SamT. While your suggestion didn't solve the problem, it did lead me to the final solution. The variable in the If statement is what seems to have been tripping up the code. As soon as I realized that I had over complicated it and thus simplified it, everything worked like a champ.:yes:yes I will however be trying your UndoAction suggestion in other parts of the project. I'm curious to know what it will do.
In the meantime though, in case anyone has a similar issue, the code below is my final solution.

Code:

---

Private Sub txtref_LostFocus()


Dim e As String  'Final output


If Not IsNull(Me.txtref.Value) Then
    e = UCase(Me.txtref.Value) 'UCase forces any leters to be captilaized.
    Me.txtref.Value = e
End If


End Sub

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Thanks for the suggestion Sam, hope to hear from you on a different question. :clap::hi:

I don't know why I left out the Me.txtRef in front of .Value

Code:

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Me.txtRef.Value = UCase(Me.txtRef.Value)

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Or, slightly faster...

Code:

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With Me.txtref
  .Value = UCase(.Value)
End with

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Anyway, I'm glad you got it working