主题：程序中使用期限设计的问题 请教？

我想在软件中用户单位表中设计了使用期限，并且加了密，用户单位表结构如下

此主题相关图片如下：ss.jpg

接下来在项目事件AfterOpenProject中写上 代码

Dim dt1 As Date
If TryConnectHost("www.163.com") Then
dt1=functions.Execute("getdate")
Else
dt1 = Date.Today
End If

try
    If  Cdate(DecryptText(zcqx,"嘻嘻网络","www.wjhans.com"))>dt1 Then '软件过期
    Else
        Forms("到期提示").show()
       End If
    catch
    Forms("到期提示格式错误").show()
 End try
 设置为显示

 

 

内部函数getdate代码为

Dim TimeServers As String(,) = New String(2, 1) {}
TimeServers(0, 0) = "time-b.timefreq.bldrdoc.gov"
TimeServers(0, 1) = "132.163.4.102"
TimeServers(1, 0) = "time-c.timefreq.bldrdoc.gov"
TimeServers(1, 1) = "132.163.4.103"
TimeServers(2, 0) = "utcnist.colorado.edu"
TimeServers(2, 1) = "128.138.140.44"

Dim portNum As Integer = 13
Dim hostName As String
Dim bytes As Byte() = New Byte(1023) {}
Dim bytesRead As Integer = 0
Dim client As New System.Net.Sockets.TcpClient()
For i As Integer = 0 To 2
    hostName = TimeServers(i, 1)
    Try
        client.Connect(hostName, portNum)
        Dim ns As System.Net.Sockets.NetworkStream = client.GetStream()
        bytesRead = ns.Read(bytes, 0, bytes.Length)
        client.Close()

        Exit For
    Catch generatedExceptionName As System.Exception
    End Try
Next
Dim sp As Char() = New Char(0) {}
sp(0) = " "c
Dim dt As System.DateTime = New DateTime()
Dim str1 As String
str1 = System.Text.Encoding.ASCII.GetString(bytes, 0, bytesRead)

Dim s As String()
s = str1.Split(sp)
dt = System.DateTime.Parse(s(1) & " " & s(2))
'得到标准时间
dt = dt.AddHours(8)
'得到北京时间
Dim getdate As Date
getdate=dt.Date
Return getdate

 

 

 

经测算：如果使用期限过期了 ，到期提示窗口有时会出现，有时不会出现，不知道什么原因，恳请老师指点，或者有没有更好的办法

解决使用期限的问题

有时候测得 有时候没有