Throw a message box when a special character is found...

Question

Again,, thought this would be pretty easy just looking to throw a message box if a special character is found.. 
Using this starter code, it works if only one special character is used, but with multiple characters, does not throw message box. 
Example ------- > : <---------Works
Example -------> :::: <---------Does not work
if(":/~/^\*$/".ToCharArray() -Contains $Sub)
[System.Windows.Forms.MessageBox]::Show("Special Characters are not supported", "Informational")
return
Djoe

Answer 1

Assuming that ":/~/^\*$/" is the set of special characters you want to filter out, and $Sub is the string you're testing, I'd do that one of two ways.  I'd either use a regular expression, or use the String.IndexOfAny() method.  (Looking for single
characters, either one works fine, but regular expressions can be made to work with much more complicated validation patterns as well.)
$Sub = "Evil \ string."
$specialCharacters = ":/~/^\*$/".ToCharArray()
if ($Sub.IndexOfAny($specialCharacters) -ge 0)
throw "Bad, scary characters!"
# Using regex:
$specialCharacterPattern = '[:/~^\\*$]'
if ($Sub -match $specialCharacterPattern)
throw "Bad, scary characters!"