My.Computer.Clock.TickCount Property
Gets the millisecond count from the computer's system timer.
' Usage
Dim value As Integer = My.Computer.Clock.TickCount
' Declaration
Public ReadOnly Property TickCount As Integer
Property Value
An Integer containing the millisecond count from the computer's system timer.
Remarks
The TickCount property provides access to the computer's system timer, which runs when the computer is active. The timer resolution is not less than 500 milliseconds.
You can use this property to make your application's behavior dependent on the length of time it has been running, or you can use it to label events, both of which are independent of the computer's clock.
Warning
When the value of the TickCount property reaches the maximum integer value (MaxValue), it then jumps to the minimum integer value (MinValue), a negative number, and continues to increment.
If the computer runs continuously, TickCount increments from zero to the maximum integer value in approximately 24.9 days.
The TickCount property increments only when the operating system is running; it pauses when the computer goes into certain power-saving modes, such as standby or hibernation. The TickCount property is unrelated to the computer's clock setting.
Use the My.Computer.Clock.LocalTime Property or My.Computer.Clock.GmtTime Property to obtain the current local date and time on this computer.
The My.Computer.Clock.TickCount property has the same behavior as the Environment.TickCount property.
Example
The following example uses the My.Computer.Clock.TickCount property to run a task in a loop for a given number of seconds, even if the computer's system time changes while it runs.
Public Sub LoopTask(ByVal secondsToRun As Integer)
Dim startTicks As Integer = My.Computer.Clock.TickCount
Do While IsTimeUp(startTicks, secondsToRun)
' Code to run for at least secondsToRun seconds goes here.
Loop
End Sub
Private Function IsTimeUp( _
ByVal startTicks As Integer, _
ByVal seconds As Integer _
) As Boolean
' This function throws an overflow exception if the
' tick count difference is greater than 2,147,483,647,
' about 24 days for My.Computer.Clock.TickCount.
' Use UInteger to simplify the code for roll over.
Dim uStart As UInteger = _
CUInt(CLng(startTicks) - Integer.MinValue)
Dim uCurrent As UInteger = _
CUInt(CLng(My.Computer.Clock.TickCount) - Integer.MinValue)
' Calculate the tick count difference.
Dim tickCountDifference As UInteger
If uStart <= uCurrent Then
tickCountDifference = uCurrent - uStart
Else
' Tick count rolled over.
tickCountDifference = UInteger.MaxValue - (uStart - uCurrent)
End If
' Convert seconds to milliseconds and compare.
Return CInt(tickCountDifference) < (seconds * 1000)
End Function
Requirements
Namespace:Microsoft.VisualBasic.Devices
Class:Clock
Assembly: Visual Basic Runtime Library (in Microsoft.VisualBasic.dll)
Availability by Project Type
Project type |
Available |
|---|---|
Windows Application |
Yes |
Class Library |
Yes |
Console Application |
Yes |
Windows Control Library |
Yes |
Web Control Library |
Yes |
Windows Service |
Yes |
Web Site |
Yes |
Permissions
No permissions are required.