Preventing accidental changes to one field on a form

[Sue22]

Hi I have a form which users will use to both create new records in a table but to also update existing records.

There is one field on the form which once it is created they should not be making any changes to. How do I stop them doing this?

I tried adding a macro (on Change) that popped up a warning box saying they were not permitted to change this field and then undid their change but it does this both to existing records and also when I try to create a new record. I only want to do it when they try to change an existing record not when the try to add a new record (the value entered in this field is the primary key)



Thanks in anticipation

[lfpm062010]

Go to form design, click on the field that you don't want anyone make any changes. Right click and select property. Find "Enabled" and/or "Locked" Change "Enabled" to "No" and/or changed "Locked" to "Yes".

[Sue22]

This doesn't work because if you do this you can't create a new record! The field is the primary key and has to be entered by the user when they first create the record I just don't want anyone to change it later on by accident!

[NTC]

In the OnCurrent event of the form property itself one would put:
If IsNull(me.FieldName) then
Me.FieldName.Unlock
Else
Me.FieldName.Lock
End If

[Sue22]

Thanks that's really helpful