Symfony：嵌入式表单集合中的独特选项

Question

I have an embedded form collection in Symfony. Which is working nice. I am working with a manytomany assocation mapping. Except i want to create (with javascript?) the form so that only unique values are available. In my example i have an Organisation which can exist of many users. When i add user "L" in this case and i want to add a second user i want to prevent that user "L" is available in the other dropdown. The way i embedded the collection of forms is exactly like the documentation of Symfony has learned me. ( http://symfony.com/doc/current/cookbook/form/form_collections.html )

Down below is an example of how it works now (in this example I want to prevent that in the dropdown the user "L" is available as an option. Thank you very much!

Answer 1

Unfortunately, there's no way you can make the HTML form behave this way. HTML forms just do not have any composite (or dependent) <select> widgets. So, the right way to go here would be:

1. validating the form server-side, so that duplicate values in two select boxes are not allowed;

2. adding some JavaScript code to the view that renders form. Perhaps this code should listen to <select> s' onChange events, and once an event is received, the option selected in the first box should either receive a disabled attribute or get deleted.