Hello OOPer, Thank you very much for your hints. I tried to develop your example code so that it works for my use case. But in the end, I failed. If the text field loses focus or a commit is triggered by the user, the last valid value should be restored in case of invalid data. I have not been able to implement this behavior. I find it challenging to find workarounds for such problems when you can't parse the library code (SwiftUI) as it is closed-source. Has anyone an idea for a working example?