Hide parts of document

Hi!

I plan on building an application that requires a code editor like this Syntax Editor with VB.NET support. In my case I would like users to edit only a part of a document (the text inside a function), so my question is whether it is possible to let the user edit only part of the document and hide the rest of it. I'd still like the user to be able to use autocomplete for things defined in the rest of the document, like e.g. Properties/Functions of the class or parameters given in the function header.

e.g. consider this document:

Imports MyApp.Common
Imports MyApp.ModuleA

Public Class TheClass
	Inherits TheSuperClass
	
	Public Function TheFunction(param as String) As String
		' User should be allowed to edit and view the code from here ...

		Console.WriteLine("Test123")
		Return param

		' ... to here, but still be able to access with autocomplete "param" or
		' any properties/functions/... of the class
	End Function
End Class

Would this be possible? Do you have any examples available?

Kind regards,

Wolfgang Steinert