I am trying to write a code that will byte swipe data in a string.

The conversion should take a 16 characters string, and swipe the first to characters with the last two, then characters three and four with character thirteen and fourteen and so on, in this format –
if the input string is

A1B2C3D4E5F6G7H8
then the converted sting will be
H8G7F6E5D4C3B2A1.

I run into problem using:
left(mystring – 2)
and
right(mystring -2)
because the string to manipulate is an input of a textbox so I fail when I try to use cross data with a StringHandling class, and I can’t figure out how to incorporate StringHandling into my form class (sorry if this is a newbie question) and without it when I try something like

Dim byte1 As String = Left(MyString, 14)I get an

error saying - ‘Public ReadOnly Property Left As Integer’ has no parameters and its return type cannot be indexed.

I am using VB.net 2010.
any help will be appriciated
thank you.