How to prevent saving based on embedded data validation?

Hi Everyone,

I have two fields, text and number fields.

If I input "aaa" into text field and "bbb" into number field and put focus on other field, it will pop up an error message, like only numbers can be input into number fields.

BUT, what if I input "aaa" into text field and "bbb" into number field and I just click save. 

What I have is that error message popped up but form is saved also.

"aaa" is saved into text field.

My Question is how can I prevent text field saving action in this case?

BTW, I know I can use context.getEventArgs().preventDefault() for customized validation.

Thank you,

Kei