In order to give your scripting-based utility equal footing with built-in LabVIEW features, though, you need to make sure anything you do with scripting can be undone or redone by the user. Thankfully, there is support in scripting for setting up Undo/Redo transactions, as illustrated by this screenshot:
Here are some details on each of the methods shown in the screenshot:
- Transaction.Begin Undo - Call this method before you start your scripting operation. The "Name" input is the text that you want users to see next to the Undo/Redo options in the Edit menu:
After calling Begin Undo, you will do all the scripting code you need to do for whatever editor operation you are performing. While doing your scripting, you need to keep track of a boolean, or some sort of flag, indicating whether or not you actually want to complete the Undo transaction, so you can make a decision between the following two methods.
- Transaction.End Undo - Did everything script ok? Assuming you didn't get any errors, and that your scripting code actually did change something on the target VI, you need to end your Undo transaction. This actually commits the scripting action to the target VI, and creates the Edit > Undo option in the menu with the Name you specified on Begin Undo.
- Transaction.Fail - Did an error occur during your scripting? Or did your scripting code not actually change anything? If either of these is the case, you probably want to Fail the transaction. This means that the transaction is not committed to the target VI, and that no new Undo option is added to the Edit menu. Notice that in my screenshot, I do not wire the error up to the Transaction.Fail method. This is because, if an error occurred in my scripting, I still want the Fail method to execute so it cancels the transaction.