How to Validate on Date in c#

Please try thic Procedure put this om main for load event
its also restrict of date change itvery use full

let me know


  private DateTime RegDate;
  private DateTime todayDate;
  private void CheckLicenceAgreement()
  {
  try
  {
  //If Not Exist The Add Date Firet Time
  if (Convert.ToString(Application.UserAppDataRegistry.GetValue("RegDate")) == "")
  {
  RegDate = DateTime.Now;
  RegDate  = RegDate.AddDays(15);

  Application.UserAppDataRegistry.SetValue("RegDate", RegDate.ToString("yyyyMMdd"));
  Application.UserAppDataRegistry.SetValue("ApplicationStart", "1");
  }
  else
  {
  //Check It

  Int32 Regdt;
  Int32 todt;
  Regdt = Convert.ToInt32(Application.UserAppDataRegistry.GetValue("RegDate"));
  todt = Convert.ToInt32(System.DateTime.Now.ToString("yyyyMMdd"));

  if ((todt > Regdt) || (Convert.ToString(Application.UserAppDataRegistry.GetValue("ApplicationStart")))=="0")
  {
  Application.UserAppDataRegistry.SetValue("ApplicationStart", "0");
  Application.Exit(); 
  }
  }
  }
  catch (Exception ex)
  {
  Application.Exit(); 
  } 
  }

I do not know what "validate my software" means.

Also, you say "without using Database". For what? Do you mean you want to show how your program works using some data but you do not want the data to be read from a database or written to a database?

Dear
try this

http://www.c-sharpcorner.com/UploadFile/sushmita_kumari/RegistryKeys102082006061720AM/RegistryKeys1.aspx

still any confusion then let me know

k.. but i did not work with registry  if its possible then please give me code...