asp.net upload

If on the local machine I change the mail.aspx.vb, then can I just upload this onto the online site? Or do I need to upload the whole three (mail.aspx, mail.aspx.vb, mail.aspx.resx)?
-If the mail.aspx.vb is changeed then would the other two i.e(mail.aspx, mail.aspx.resx) change internally?

Only what's changed.

If you are compiling the project in a code behind, the vb file isn't even necessary, instead, you need the dll in the bin folder.