How can I limited the no. of picture upload"using upload care" to my form by "reading" to another field input?

hello, I try to limited the no. of picture to be uploaded to this form = the frame no. that input by the user.

i tired to input a number into the widget setting and it works, but seems it cannot "read" the {frameCount}

I tried but fail, any other way i can do that? 

Hello,

I am sorry, but at this time we have no upload widget that supports dynamical parameters as limits. You might need to enter actual number of files to be uploaded.