The name of the property should be something meaningful to you and whoever has to maintain your code should you pass it on to someone else. I would call it lUseFormEditStatus. You are missing the ENDCASE. I would have code more like:

PROC Refresh
WITH This
   DO CASE
      CASE ISNULL(.xyz) or VARTYPE(.xyz) <> "L"
         * nothing to do
      CASE .xyz
         * set enabled state to the same value of forms editmode
         .Enabled = ThisForm.lEditMode
      OTHERWISE
         * set enabled state to the opposite value of forms editmode
         .Enabled = (NOT ThisForm.lEditMode)
   ENDCASE
ENDWITH
ENDPROC

Ideally, since you say this is a custom button class, I would create an Assing method for this property in the button class. WHenever the property is assigned a value, return FALSE if the new value being assigned to it is not logical. Then you have no need to check to see if it is null or not logical.

>Hi, folks!
>
>Here is a little "competition" <vbg>:
>
>I have a class called "MyButton" with a property "xyz"!
>
>In the refresh event I put the following code:
>

>PROC Refresh
>WITH This
>	DO CASE
>	CASE ISNULL(.xyz)
>		* nothing to do
>	CASE .xyz = .T.
>		* set enabled state to the same value of forms editmode
>		.Enabled = ThisForm.lEditMode
>	CASE .xyz = .F.
>		* set enabled state to the opposite value of forms editmode
>		.Enabled = (NOT ThisForm.lEditMode)
>ENDWITH
>ENDPROC
>

>
>Now the question: What is a good, proper, correct name of the property "xyz"?