C 30 Days From Todays Date

Question

I need my application to expire 30 days from today  I will store the current date in the application config How will I check if the application has expired   I don t mind if the user changed the clock back and the app works  too stupid a user to do that     if  appmode     Trial

User · Answer

DateTime Now Add -30   Gives you the date 30 days back from now

User · Answer

A possible solution would be on first run  create a file containing the current date and put it in IsolatedStorage  For subsequent runs  check the contents of the file and compare with the current date  if the date difference is greater than 30 days  inform the user and close the application

User · Answer

string dateInString    01 10 2009    DateTime startDate   DateTime Parse dateInString   DateTime expiryDate   startDate AddDays 30   if  DateTime Now  gt  expiryDate            trial expired

User · Answer

if  cmb mode of service SelectedItem    null  amp  amp  cmb term of service SelectedItem    null                                if  cmb mode of service SelectedIndex  gt  0  amp  amp  cmb term of service SelectedIndex  gt  0                                        if  cmb mode of service SelectedItem ToString       Single Service Installation     cmb term of service SelectedItem ToString       Single Time                                                 int c2   1                          char c1    A                           DataRow dr   dt NewRow                            dr  SN     c2                            dr  serviceid     txt service id Text    -    c1                            dr  servicedate     service start date Text                          dr  servicestatus      Pending                           dr  serviceexcutive      Not Alowed                           dt Rows Add dr                           dataGridView1 DataSource   dt                           txtexpirydate Text    Convert ToDateTime service start date Text  AddDays 1   ToString                                               else                                                  if  cmb mode of service SelectedItem ToString       Weekly Service                                                         int year   0                              if  cmb term of service SelectedItem ToString       One Year                                                                 year   1                                                             if  cmb term of service SelectedItem ToString       Two Year                                                                 year   2                                                             if  cmb term of service SelectedItem ToString       three year                                                                 year   3                                                             DateTime currentdate   Convert ToDateTime service start date Text                               DateTime Enddate   currentdate AddYears  year                               txtexpirydate Text   Enddate ToString                                 char c1    A                               int c2   1                              for  var dt1   currentdate AddDays 7   dt1  lt   Enddate  dt1   dt1 AddDays 7                                                                 DataRow dr   dt NewRow                                    dr  SN     c2                                    dr  serviceid     txt service id Text    -    c1                                    dr  servicedate     dt1 ToString                                    dr  servicestatus      Pending                                   dr  serviceexcutive      Not Alowed                                     txtexpirydate Text   dt1 ToString                                    dt Rows Add dr                                                              dataGridView1 DataSource   dt                                                      if  cmb mode of service SelectedItem ToString       Fortnight Service                                                         int year   0                              if  cmb term of service SelectedItem ToString       One Year                                                                 year   1                                                             if  cmb term of service SelectedItem ToString       Two Year                                                                 year   2                                                             if  cmb term of service SelectedItem ToString       three year                                                                 year   3                                                             DateTime currentdate   Convert ToDateTime service start date Text                               DateTime Enddate   currentdate AddYears  year                               txtexpirydate Text   Enddate ToString                                 char c1    A                               int c2   1                              for  var dt1   currentdate AddDays 15   dt1  lt   Enddate  dt1   dt1 AddDays 15                                                                 DataRow dr   dt NewRow                                    dr  SN     c2                                    dr  serviceid     txt service id Text    -    c1                                    dr  servicedate     dt1 ToString                                    dr  servicestatus      Pending                                   dr  serviceexcutive      Not Alowed                                       txtexpirydate Text   dt1 ToString                                    dt Rows Add dr                                                              dataGridView1 DataSource   dt                                                      if  cmb mode of service SelectedItem ToString       Monthly Service                                                         int year   0                              if  cmb term of service SelectedItem ToString       One Year                                                                 year   1                                                             if  cmb term of service SelectedItem ToString       Two Year                                                                 year   2                                                             if  cmb term of service SelectedItem ToString       three year                                                                 year   3                                                             DateTime currentdate   Convert ToDateTime service start date Text                               DateTime Enddate   currentdate AddYears  year                               txtexpirydate Text   Enddate ToString                                 char c1    A                               int c2   1                              for  var dt1   currentdate AddDays 30   dt1  lt   Enddate  dt1   dt1 AddDays 30                                                                 DataRow dr   dt NewRow                                    dr  SN     c2                                    dr  serviceid     txt service id Text    -    c1                                    dr  servicedate     dt1 ToString                                    dr  servicestatus      Pending                                   dr  serviceexcutive      Not Alowed                                      txtexpirydate Text   dt1 ToString                                    dt Rows Add dr                                                              dataGridView1 DataSource   dt                                                       if  cmb mode of service SelectedItem ToString       Trimister Service                                                         int year   0                              if  cmb term of service SelectedItem ToString       One Year                                                                 year   1                                                             if  cmb term of service SelectedItem ToString       Two Year                                                                 year   2                                                             if  cmb term of service SelectedItem ToString       three year                                                                 year   3                                                             DateTime currentdate   Convert ToDateTime service start date Text                               DateTime Enddate   currentdate AddYears  year                               txtexpirydate Text   Enddate ToString                                 char c1    A                               int c2   1                              for  var dt1   currentdate AddDays 90   dt1  lt   Enddate  dt1   dt1 AddDays 90                                                                 DataRow dr   dt NewRow                                    dr  SN     c2                                    dr  serviceid     txt service id Text    -    c1                                    dr  servicedate     dt1 ToString                                    dr  servicestatus      Pending                                   dr  serviceexcutive      Not Alowed                                      txtexpirydate Text   dt1 ToString                                    dt Rows Add dr                                                              dataGridView1 DataSource   dt                                                      if  cmb mode of service SelectedItem ToString       Half Yearly Service                                                         int year   0                              if  cmb term of service SelectedItem ToString       One Year                                                                 year   1                                                             if  cmb term of service SelectedItem ToString       Two Year                                                                 year   2                                                             if  cmb term of service SelectedItem ToString       three year                                                                 year   3                                                             DateTime currentdate   Convert ToDateTime service start date Text                               DateTime Enddate   currentdate AddYears  year                               txtexpirydate Text   Enddate ToString                                 char c1    A                               int c2   1                              for  var dt1   currentdate AddDays 180   dt1  lt   Enddate  dt1   dt1 AddDays 180                                                                 DataRow dr   dt NewRow                                    dr  SN     c2                                    dr  serviceid     txt service id Text    -    c1                                    dr  servicedate     dt1 ToString                                    dr  servicestatus      Pending                                   dr  serviceexcutive      Not Alowed                                       txtexpirydate Text   dt1 ToString                                    dt Rows Add dr                                                              dataGridView1 DataSource   dt                                                      if  cmb mode of service SelectedItem ToString       Yearly Service                                                         int year   0                              if  cmb term of service SelectedItem ToString       One Year                                                                 year   1                                                             if  cmb term of service SelectedItem ToString       Two Year                                                                 year   2                                                             if  cmb term of service SelectedItem ToString       three year                                                                 year   3                                                             DateTime currentdate   Convert ToDateTime service start date Text                               DateTime Enddate   currentdate AddYears  year                               txtexpirydate Text   Enddate ToString                                 char c1    A                               int c2   1                              for  var dt1   currentdate AddDays 365   dt1  lt   Enddate  dt1   dt1 AddDays 365                                                                 DataRow dr   dt NewRow                                    dr  SN     c2                                    dr  serviceid     txt service id Text    -    c1                                    dr  servicedate     dt1 ToString                                    dr  servicestatus      Pending                                   dr  serviceexcutive      Not Alowed                                     txtexpirydate Text   dt1 ToString                                    dt Rows Add dr                                                              dataGridView1 DataSource   dt

User · Answer

You need to store the first run time of the program in order to do this   How I d probably do it is using the built in application settings in visual studio   Make one called InstallDate which is a User Setting and defaults to DateTime MinValue or something like that  e g  1 1 1900    Then when the program is run the check is simple   if  appmode     trial          If the FirstRunDate is MinValue  it s the first run  so set this value up   if  Properties Settings Default FirstRunDate    DateTime MinValue          Properties Settings Default FirstRunDate   DateTime Now      Properties Settings Default Save               Now check whether 30 days have passed since the first run date   if  Properties Settings Default FirstRunDate AddMonths 1   lt  DateTime Now             Do whatever you want to do on expiry  exception message shut down etc           User settings are stored in a pretty weird location  something like C  Documents and Settings YourName Local Settings Application Data  so it will be pretty hard for average joe to find it anyway   If you want to be paranoid  just encrypt the date before saving it to settings   EDIT  Sigh  misread the question  not as complex as I thought

User · Answer

Ed courtenay   James  I have one stupid question  How to keep user away from this file  File containing expiry date   If the user has installation rights  then obviously user has access to view files also  Changing the extension of file wont help  So  how to keep this file safe and away from users hands

User · Answer

One I can answer confidently   DateTime expiryDate   DateTime Now AddDays 30     Or possibly - if you just want the date without a time attached which might be more appropriate   DateTime expiryDate   DateTime Today AddDays 30

User · Answer

A better solution might be to introduce a license file with a counter  Write into the license file the install date of the application  during installation   Then everytime the application is run you can edit the license file and increment the count by 1  Each time the application starts up you just do a quick check to see if the 30 uses of the application has been reached i e   if  LicenseFile Counter    30         go into expired mode   Also this will solve the issue if the user has put the system clock back as you can do a simple check to say   if  LicenseFile InstallationDate  lt  SystemDate         go into expired mode  as punishment for trying to trick the app      The problem with your current setup is the user will have to use the application every day for 30 days to get their full 30 day trial

User · Answer

string   servers   new string              nist1-ny ustiming org            nist1-nj ustiming org            nist1-pa ustiming org            time-a nist gov            time-b nist gov            nist1 aol-va symmetricom com            nist1 columbiacountyga gov            nist1-chi ustiming org            nist expertsmi com            nist netservicesgroup com             string dateStart  dateEnd   void SetDateToday                 Random rnd   new Random            DateTime result   new DateTime            int found   0          foreach  string server in servers OrderBy s   gt  rnd NextDouble    Take 5                         Console Write                   try                               string serverResponse   string Empty                  using  var reader   new StreamReader new System Net Sockets TcpClient server  13  GetStream                                           serverResponse   reader ReadToEnd                        Console WriteLine serverResponse                                      if   string IsNullOrEmpty serverResponse                                         string   tokens   serverResponse Split                           string   date   tokens 1  Split                           string time   tokens 2                       string properTime                       dateStart   date 2          date 0          date 1                        int month   Convert ToInt16 date 0    day   Convert ToInt16 date 2    year   Convert ToInt16 date 1                        day   day   30                      if   month   2     0                                                  MAX DAYS IS 30                         if  day  gt  30                                                        day   day - 30                              month                                if  month  gt  12                                                                month   1                                  year                                                                                                      else                                                 MAX DAYS IS 31                         if  day  gt  31                                                        day   day - 31                              month                                if  month  gt  12                                                                month   1                                  year                                                                                                      string sday  smonth                      if  day  lt  10                                                sday    0    day                                            if  month  lt  10                                                smonth    0    month                                            dateEnd   sday         smonth         year ToString                                                  catch                                  Ignore exception and try the next server                                 if  found    0                        MessageBox Show this   Internet Connection is required to complete Registration  Please check your internet connection and try again     Not connected   MessageBoxButtons OK  MessageBoxIcon Information               Success   false                    I saw that code in some part of some website  Doing the example above exposes a glitch  Changing the current Time and Date to the start date would prolong the application expiration   The solution  Refer to a online time server

User · Answer

A bit late to this question  but I created a class with all the handy methods needed to create a fully functional time trial in C   Rather than your application config  I write the expiry time to the Windows Application Data path  and that will also remain persistent even after the program has closed  it s also tricky to find the path for the average user    Fully documented and simple to use  I hope someone finds it useful   public class TimeTrialManager       private long expiryTime 0      private string softwareName           private string userPath         private bool useSeconds   false       public TimeTrialManager string softwareName            this softwareName   softwareName             Create folder in Windows Application Data folder for persistence          userPath   Environment GetFolderPath Environment SpecialFolder ApplicationData  ToString            softwareName     prefs             if   Directory Exists userPath   Directory CreateDirectory Path GetDirectoryName userPath            userPath     expiryinfo txt                 Use this method to check if the expiry has already been created  If        it has  you don t need to call the setExpiryDate   method ever again      public bool expiryHasBeenStored            return File Exists userPath                 Use this to set expiry as the number of days from the current time         This should be called just once in the program s lifetime for that user      public void setExpiryDate double days             DateTime time   DateTime Now AddDays days           expiryTime   time ToFileTimeUtc            storeExpiry expiryTime ToString              useSeconds   false                Like above  but set the number of seconds  This should be just used for testing        as no sensible time trial would allow the user seconds to test the trial out      public void setExpiryTime double seconds              DateTime time   DateTime Now AddSeconds seconds           expiryTime   time ToFileTimeUtc            storeExpiry expiryTime ToString             useSeconds   true                Check for this in a background timer or whenever else you wish to check if the time has run out     public bool trialHasExpired               if  File Exists userPath   return false          if  expiryTime    0     expiryTime   Convert ToInt64 File ReadAllText userPath            if  DateTime Now ToFileTimeUtc    gt   expiryTime  return true  else return false                This method is optional and isn t required to use the core functionality of the class        Perhaps use it to tell the user how long he has left to trial the software     public string expiryAsHumanReadableString bool remaining false            DateTime dt   new DateTime            dt   DateTime FromFileTimeUtc expiryTime           if  remaining    false  return dt ToShortDateString           dt ToLongTimeString            else               if  useSeconds  return dt Subtract DateTime Now  TotalSeconds ToString                else return  dt Subtract DateTime Now  TotalDays   ToString                            This method is private to the class  so no need to worry about it     private void storeExpiry string value             try   File WriteAllText userPath  value             catch  Exception ex    MessageBox Show ex Message                Here is a typical usage of the above class  Couldn t be simpler   TimeTrialManager ttm  private void Form1 Load object sender  EventArgs e        ttm   new TimeTrialManager  TestTime        if   ttm expiryHasBeenStored    ttm setExpiryDate 30      Expires in 30 days time    private void timer1 Tick object sender  EventArgs e        if  ttm trialHasExpired      MessageBox Show  Trial over        Environment Exit 0

User · Answer

DateTime  expiryDate   DateTime Now   TimeSpan FromDays 30

User · Answer

DateTime AddDays does that   DateTime expires   yourDate AddDays 30

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