When VB.NET 1.0 was introduced, one of the biggest changes was that all of Microsoft's generated source code was included and available to you as a programmer in your project. VB.old only created indecipherable p-code that you couldn't see and you couldn't change. But even though the generated code was in your program, nearly all the time it was a bad idea to change any of it. If you don't know what you're doing, you're almost certain to 'break' your project by changing Microsoft's generated code.
In VB.NET 1.0, all this generated code was only protected by being enclosed in a Region section of the program where it was only one click away from being viewable and changable as part of your source code. Starting with VB.NET 2005 (Framework 2.0), Microsoft put it in an entirely different file using "partial classes". But the Region directive is still available and you can use it to organize your own code.
First, let's code a simple program just to show how Region works.
Public Class Form1
Dim myInstance As LongAndIntricateCode
End Class
Public Class LongAndIntricateCode
' Assume you paid a professional
' statistician a zillion dollars
' to code this custom calculation that
' nobody in your company understands.
' That's what is in this class!
End Class
You could compile this into a DLL to protect it. Or you could use the partial class idea that Visual Studio uses or even just a separate class file. But the easiest and quickest way to keep it out of the way and still make it part of the same file is to use the Region directive. That would make the code look like this:
Public Class Form1
Dim myInstance As LongAndIntricateCode
End Class
Don't Touch This!
Just surround the code you want to "disappear" with:
#Region "Don't Touch This!"
...
#End Region
For debugging purposes, you can use this as a way to bring parts of your code "closer together" so you can see them on the same screen:
' Code that I'm debugging
#Region "Make This Disappear"
' 5,000 lines of code that is irrelevant
#End Region
' More code that I'm debugging
You can't use a Region or an End Region inside a function or subroutine. In other words, this doesn't work:
Public Sub ThisSub()
#Region "Don't Touch This!"
' The code for this subroutine
#End Region
End Sub
That's OK ... Visual Studio will collapse subroutines without a Region directive.
But you can nest Regions. In other words, this does work:
#Region "Outer Region"
Public Class FirstClass
' Code for FirstClass
End Class
#Region "Inner Region"
Public Class SecondClass
'Code for SecondClass
End Class
#End Region
#End Region
If you "borrow" code from the Internet, look for Regions in it before you add it to your code. A few bad guys have been known to embed their bad stuff inside a Region to keep it from being noticed.
