how to make a trial software

[adol]

Hello,
I need my app to expire after 30 days of use. How can I do this?
If you dont have the code just tell me the process to make it a trial one then I'll research a little more.

Thanks in advance

adol

[nemaroller]

You could write the system date to a registry key when the app first runs...

Or you could write the system date to a data file in the Windows directory (no one ever looks there)...

[gamezfreakuk]

See a thing called "search" at the top, use it, many people have asked this question

[MidgetsBro]

You need to get the date when the program first runs, then store it somewhere in the registry, most likely encrypted, then when the program loads each time after that, it should check that encrypted registry key. If the current date is 30 days after the first date the program was run, then you need to disable the program. The thing is that this isn't the best way to release software. People can easily find ways to crack software with full features and 30 day trials. It is better to strip some code out of the trial version, like completely remove the option to save. Then they cannot crack the program, and you will end up making more money if people want the software.

[ejy]

Begs the question....

what is the most accurate way to check if one "Date" is more than 30 days past another "Date"?

[peet]

here is a sample. not a good protection, but it should give you some ideas

'Author: Reginald Wheat 
 
Option Explicit
 
Public Function DateGood(NumDays As Integer) As Boolean
    'The purpose of this module is to allow you to place a time
    'limit on the unregistered use of your shareware application.
    'This module can not be defeated by rolling back the system clock.
    'Simply call the DateGood function when your application is first
    'loading, passing it the number of days it can be used without
    'registering.
    '
    'Ex: If DateGood(30)=False Then
    ' CrippleApplication
    ' End if
    'Register Parameters:
    ' CRD: Current Run Date
    ' LRD: Last Run Date
    ' FRD: First Run Date
 
    Dim TmpCRD As Date
    Dim TmpLRD As Date
    Dim TmpFRD As Date
 
    TmpCRD = Format(Now, "m/d/yy")
    TmpLRD = GetSetting(App.EXEName, "Param", "LRD", "1/1/2000")
    TmpFRD = GetSetting(App.EXEName, "Param", "FRD", "1/1/2000")
    DateGood = False
 
    'If this is the applications first load, write initial settings
    'to the register
    If TmpLRD = "1/1/2000" Then
        SaveSetting App.EXEName, "Param", "LRD", TmpCRD
        SaveSetting App.EXEName, "Param", "FRD", TmpCRD
    End If
    'Read LRD and FRD from register
    TmpLRD = GetSetting(App.EXEName, "Param", "LRD", "1/1/2000")
    TmpFRD = GetSetting(App.EXEName, "Param", "FRD", "1/1/2000")
 
    If TmpFRD > TmpCRD Then 'System clock rolled back
        DateGood = False
    ElseIf Now > DateAdd("d", NumDays, TmpFRD) Then 'Expiration expired
        DateGood = False
    ElseIf TmpCRD > TmpLRD Then 'Everything OK write New LRD date
        SaveSetting App.EXEName, "Param", "LRD", TmpCRD
        DateGood = True
    ElseIf TmpCRD = Format(TmpLRD, "m/d/yy") Then
        DateGood = True
    Else
        DateGood = False
    End If
End Function
 
 
'Usage 
 
 Private Sub Form_Activate()
    If Not DateGood(30) Then
        MsgBox "Trial Period Expired!", vbExclamation, "Unregistered application"
        Unload Me
    End If
End Sub