Try adding the other class as an extension in your opening <apex:page> tag. You can do this for multiple classes by separating them with commas.
<apex:page controller="SomeApex_Controller"
extensions="FileRemoting,AnotherHelperClass">
Edit:
To resolve the custom controller error you're getting, you can either add a constructor to the FileRemoting class for your particular class that wants to use the helper remoting methods, or derive the constructor from a base class that your initial controller then extends.
Option 1:
public class FileRemoting {
public FileRemoting(GlobalSearch_Custom controller) {
// do something, although you don't have to do anything here
}
// you will need to add separate constructors for each page
// that you want to leverage this class (unless they use the same controller)
}
Option 2:
public abstract class CustomControllerBase {
// you'd probably just want to leave this blank rather than force extending classes to implement something
}
public class GlobalSearch_Custom extends CustomControllerBase {
// custom controller class body
// note that any other controller that wants to use FileRemoting methods will
// also need to extend the CustomControllerBase class
}
public class FileRemoting {
public FileRemoting(CustomControllerBase controller) {
// do something, although you don't have to do anything here
}
}
Either of these options should allow you to reference the FileRemoting class as an extension in your VF page.
