How To Use Region in C# and VB.Net

In C#

#Region "Don't Touch This!"
...
#EndRegion

In VB.Net

#Region "Don't Touch This!"
...
#End Region

So in essence, there’s not much of a difference apart from the space in between End and Region

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. If you ever find yourself the need to put #Region inside a subroutine/function, it usually means that the subroutine/function is getting a bit big and it’s time to refactor (modularize) it.

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