Article
11/18/2011

Timer Constructor (TimerCallback, Object, UInt32, UInt32)

Microsoft Silverlight will reach end of support after October 2021. Learn more.

Initializes a new instance of the Timer class, using 32-bit unsigned integers to measure time intervals.

This API is not CLS-compliant.

Namespace: System.Threading
Assembly: mscorlib (in mscorlib.dll)

Syntax

'Declaration
<CLSCompliantAttribute(False)> _
<SecuritySafeCriticalAttribute> _
Public Sub New ( _
    callback As TimerCallback, _
    state As Object, _
    dueTime As UInteger, _
    period As UInteger _
)

[CLSCompliantAttribute(false)]
[SecuritySafeCriticalAttribute]
public Timer(
    TimerCallback callback,
    Object state,
    uint dueTime,
    uint period
)

Parameters

callback
Type: System.Threading.TimerCallback
A delegate that represents a method to be executed.

state
Type: System.Object
An object that contains information to be used by the callback method, or nulla null reference (Nothing in Visual Basic).

dueTime
Type: System.UInt32
The amount of time to delay before callback is invoked, in milliseconds. Specify UInt32.MaxValue to prevent the timer from starting. Specify 0 (zero) to start the timer immediately.

period
Type: System.UInt32
The time interval between invocations of callback, in milliseconds. Specify UInt32.MaxValue to disable periodic signaling.

Exceptions

Exception	Condition
ArgumentNullException	The callback parameter is nulla null reference (Nothing in Visual Basic).

Remarks

The delegate specified by the callback parameter is invoked once after dueTime elapses, and thereafter each time the period time interval elapses.

Note:
Visual Basic users can omit the TimerCallback constructor, and simply use the AddressOf operator when specifying the callback method. Visual Basic automatically calls the correct delegate constructor.

If dueTime is 0 (zero), callback is invoked immediately. If dueTime is UInt32.MaxValue, callback is not invoked; the timer is disabled but can be re-enabled by calling the Change method.

If period is 0 (zero) or UInt32.MaxValue, and dueTime is not UInt32.MaxValue, callback is invoked once; the periodic behavior of the timer is disabled but can be re-enabled using the Change method.

The method specified for callback should be reentrant, because it is called on ThreadPool threads. The method can be executed simultaneously on two thread pool threads if the timer interval is less than the time required to execute the method, or if all thread pool threads are in use and the method is queued multiple times.

Version Information

Silverlight

Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

XNA Framework

Supported in: Xbox 360, Windows Phone OS 7.0

Platforms

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.

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