what is the use of cchar and chrw methods?

Question

If e.KeyChar = CChar(ChrW(Keys.Back)) Or e.KeyChar = CChar(".") Then

e.Handled = False
Else
e.Handled = True....

i want explanations for the above code..i know this code for validate the textbox in vb.net..

but i can't understand the use of CChar,ChrW,keys.back...

so telll me wht is use of CChar,ChrW,Keys.back>

Alan · Answer

CChar() takes a String as an argument and converts the first character to the Char datatype which represents a unicode character (2 bytes). For example: Dim c As Char = CChar(abc) ' c is equal to ac ChrW() takes an Integer as an argument and returns the unicode character (as a Char) which has that number. For example: Dim letter As Char = ChrW(65) ' letter is equal to Ac Notice that to get a Char literal in VB you follow it with 'c'. So Dim char1 As String = B ' String literal Dim char2 As Char = Bc ' Char literal Although these may look the same they are in fact different data types. So in the expression: CChar(ChrW(Keys.Back)) Keys.Back is a member of the Keys Enum (similar to an Integer0 and so you need to apply ChrW() to it to get its Char equivalent. The user of CChar() is superfluous because ChrW is already a Char so you should just use ChrW(Keys.Back) instead.