validate IP

validate IP

• cderose

  Try regular expressions:

  string ip = "192.168.100.100";

  Regex regex = new Regex("[0-2][0-9][0-9]\\.[0-2][0-9][0-9]\\.[0-2][0-9][0-9]\\.[0-2][0-9][0-9]");

  Console.WriteLine(regex.Match(ip).Success);

  The expression itself might not be sufficient (depends on your input string), it requires each numer to have 3 digits. A better can be found here: http://www.regular-expressions.info/examples.html

  
  

• raq

  Translated:

  public function IsAddressValid(byval addrString as string) as Boolean
  
  Dim address as IPAddress = nothing
  return IPAddress.TryParse(addrString, address)
  

  end sub

  
  
  

• levitymn

  agrt wrote:

  You could also use System.Net.IPAddress.TryParse. Here's an example: public bool IsAddressValid(string addrString) { IPAddress address; return IPAddress.TryParse(addrString, out address); } Creating the IPAddress may seem excessive if you're just doing validation, but it may perform better than using a regular expression. Your results may vary.

  hi

  i have the same problem and have not much expirience with VB 2005. can u please explain this for VB

  thanks

  
  

• doener

  hi ,

  i would prefer the IPAddress.TryParse instead of creating a whole regex expression.

  i feel Regex is more costly.Also it uses tryparse so no exceptions causing performance issues.

  thanks

  vinothkumar

  
  
  

• dki

  You could also use System.Net.IPAddress.TryParse. Here's an example:

  public bool IsAddressValid(string addrString)
  {
  IPAddress address;
  return IPAddress.TryParse(addrString, out address);
  }
  
  Creating the IPAddress may seem excessive if you're just doing validation, but it may perform better than using a regular expression. Your results may vary.
  

  
  
  

• humbroll

  yes that is correct

  Regex is expensive but should be used when carrying out large operations as its more worthwhile.

  I wonder if it can parse IPv6....

  
  
  

• thomaskremmel

  it works.^^
  
• validate IP