How to develop a time limited version of software 1

[Guest_imported]

If i want add a functionality to my COM Object that after certain number of days the evaluation version should expire and user can not use the same untill he purchases a full license.

Any leads on this particular work are appreciated. And It would be more helpful if some one posts an code clip or some site link.

Regards
Kris

 

[Phathi]

Hi,

If you still need this...


Option Explicit

Public Function DateGood(NumDays As Integer) As Boolean
Dim TmpCRD As Date
Dim TmpLRD As Date
Dim TmpFRD As Date

TmpCRD = Format(Now, "m/d/yy&quot
TmpLRD = GetSetting(App.EXEName, _
"Param", "LRD", "1/1/2000&quot
TmpFRD = GetSetting(App.EXEName, _
"Param", "FRD", "1/1/2000&quot
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&quot
TmpFRD = GetSetting(App.EXEName, "Param", "FRD", "1/1/2000&quot

If TmpFRD > TmpCRD Then 'System clock rolled back
DateGood = False
msgbox "System Date Has Been Tampered With."
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&quot Then
DateGood = True
Else
DateGood = False
End If
End Function


Then use it


Private Sub Form_Activate()
If Not DateGood(30) Then
MsgBox "Your 30 Day Trial Period Is Over!", _
vbExclamation, _
"Unregistered application"
Unload Me
End If
End Sub


You'll however have to build some way of accepting a registration key depending on your preferred method/algorithm.

Ciao
Phathi :-V