Raja, Thanks a lot for the wishes.
Poster, thanks for adding reference for C#.
To make the things little more clearer i am adding example below.
Dim testString = "TestingStringHere"
Mid(testString, 5) = "..Bore.." ' it is Mid statement
Console.WriteLine(testString) ' returns Test..Bore..gHere - its replacing string
Dim midstring As String = "TestingStringHere"
midstring = Mid(midstring, 8, 6) ' it is Mid function
Console.WriteLine(midstring) ' returns string - its just extracting string
Hope this can help to understand "MID" better...!
Let me know in case of any concerns with the same.