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IsControl  
Method  
Returns true if a given character is a control character
Char Structure
System NameSpace
CF1.  Function IsControl ( UnicodeChar : Char; ) : Boolean;
NotCF2.  Function IsControl ( CharString:StringCharString : String; Index : Integer; ) : Boolean; Static;
CF : Methods with this mark are Compact Framework Compatible
Description
Returns true if the Unicode character, or the character at Index position in CharString is a control character.
 
Examples of control characters :
 
Tab
10 Line feed
13 Carriage return
Notes
Very Important : Methods in .Net treat strings as starting at 0, unlike traditional Delphi where they started at 1.

Static methods are not methods of an object - they are simply class functions or procedures available at any time.
Microsoft MSDN Links
System
System.Char
 
 
An example of both syntaxes
program Project1;
{$APPTYPE CONSOLE}

var
  myChar : Char;
  myStr  : String;

begin
  myChar := Chr(13);  // Carriage return

  if System.Char.IsControl(myChar)
  then Console.WriteLine('Chr(13) is a control character')
  else Console.WriteLine('Chr(13) is not a control character');

  myStr := '1234';
  if System.Char.IsControl(myStr, 2)    // Note 0 based index
  then Console.WriteLine(myStr[3] + ' is a control character') // 1 based
  else Console.WriteLine(myStr[3] + ' is not a control character');

  Console.ReadLine;
end.
Show full unit code
  Chr(13) is a control character
  3 is not a control character
 
 
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