干嘛不直接用系统时间呢？
让客户满意是我们工作的目标，不断超越客户的期望值来自于我们对这个行业的热爱。我们立志把好的技术通过有效、简单的方式提供给客户，将通过不懈努力成为客户在信息化领域值得信任、有价值的长期合作伙伴，公司提供的服务项目有：空间域名、虚拟空间、营销软件、网站建设、陇县网站维护、网站推广。
在start按下时 textbox4.text=now
在stop按下时 textbox5.text=now
在Timer控件里面编程，interval设为1分钟，判断系统时间为上午10点或者下午5点30分，启动发送邮件的程序，如果系统时间不是上述时间，则退出。
form 的load事件中加一句：timer1.interval=1000
在一个按钮里面加入一句触发timer事件开始计时的代码：
timer1.enabled=true
timer的tick事件中加入这么两句：
textbox1.backcolor=color.red
timer1.enabled=false
你是指Internet上的国际标准时间吗。
先加入控件 AxWinsock1 在.Com中Microsoft.Winsock
Public Class Form1
Private Declare Sub Sleep Lib "kernel32" (ByVal dwMilliseconds As Integer)
Dim NoSrv As Boolean
Dim TimeFromNet As String
Dim OldTime As Date
Dim NewTime As Date
Dim MyDate As Date
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
If AxWinsock1.CtlState MSWinsockLib.StateConstants.sckClosed Then AxWinsock1.Close()
AxWinsock1.Protocol = MSWinsockLib.ProtocolConstants.sckTCPProtocol
NetTime("") '首先取中科院国家授时中心时间
If NoSrv Or TimeFromNet = "" Then
NetTime("time.nist.gov") '取美国标准技时院时间
If NoSrv Or TimeFromNet = "" Then
MsgBox("检测不到网络标准时间服务器time.nist.gov！")
Else
NetTime("time.nist.gov")
If TimeFromNet = "" Then
MsgBox("网络标准时间服务器time.nist.gov超时！")
Else
MyDate = Mid(TimeFromNet, 8, 8)
OldTime = Mid(TimeFromNet, 17, 8)
NewTime = TimeSerial((Hour(OldTime) + 8) Mod 24, Minute(OldTime), Second(OldTime))
Dim MyTime As DateTime = MyDate Space(1) NewTime
MsgBox(MyTime)
'SetWindowsClock(MyTime)
End If
End If
Else
'使网络误差时间小，第2次再中科院国家授时中心时间
NetTime("")
If TimeFromNet = "" Then
MsgBox("网络标准时间服务器超时！")
Else
MyDate = Mid(TimeFromNet, 8, 8)
NewTime = Mid(TimeFromNet, 17, 8)
Dim MyTime As DateTime = MyDate Space(1) NewTime
MsgBox(MyTime)
'SetWindowsClock(MyTime)
End If
End If
End Sub
Private Sub NetTime(ByVal TimeSrv As String)
NoSrv = False
TimeFromNet = ""
If AxWinsock1.CtlState MSWinsockLib.StateConstants.sckClosed Then AxWinsock1.Close()
AxWinsock1.RemoteHost = TimeSrv ' "" 或 "time.nist.gov"
AxWinsock1.RemotePort = 13
AxWinsock1.LocalPort = 0
AxWinsock1.Connect()
Do While TimeFromNet = ""
If NoSrv Then Exit Do
Sleep(55)
System.Windows.Forms.Application.DoEvents()
Loop
If AxWinsock1.CtlState MSWinsockLib.StateConstants.sckClosed Then AxWinsock1.Close()
End Sub
Private Sub AxAxWinsock1_CloseEvent(ByVal sender As Object, ByVal e As System.EventArgs) Handles AxWinsock1.CloseEvent
AxWinsock1.Close()
End Sub
Private Sub AxAxWinsock1_DataArrival(ByVal sender As Object, ByVal e As AxMSWinsockLib.DMSWinsockControlEvents_DataArrivalEvent) Handles AxWinsock1.DataArrival
AxWinsock1.GetData(TimeFromNet)
End Sub
Private Sub AxAxWinsock1_Error(ByVal sender As Object, ByVal e As AxMSWinsockLib.DMSWinsockControlEvents_ErrorEvent) Handles AxWinsock1.Error
NoSrv = True
End Sub
End Class
定时器中处理
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Timer1.Interval = 10 '10毫秒刷新一次
Timer1.Start() '开启定时器
End Sub
Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
Label1.Text = Now
End Sub
'添加一个label标签名字label1 用来显示时间
'再添加一个timer控件 名字timer1 interval属性=1000 用来计时
'窗体添加代码
Dim t As Date '用来记录时间
Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As _
System.EventArgs) Handles Timer1.Tick
t = t.AddSeconds(1)
Label1.Text = "登录时间:" t.TimeOfDay.ToString
End Sub