Class Watcher

An abstract class for establishing a watcher, that can monitor and signal changes of a resource by raising the Changed event.

Inheritance
System.Object
Watcher
DataWatcher
NetWatcher
Implements
System.IDisposable
Namespace: Cuemon.Runtime
Assembly: Cuemon.Runtime.dll
Syntax
public abstract class Watcher : IDisposable

Constructors

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Watcher()

Initializes a new instance of the Watcher class, where the signaling is initiated immediately and hereby followed by a periodic signaling every 2 minutes.

Declaration
protected Watcher()
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Watcher(TimeSpan)

Initializes a new instance of the Watcher class, where the signaling is initiated immediately.

Declaration
protected Watcher(TimeSpan period)
Parameters
Type Name Description
System.TimeSpan period

The time interval between periodic signaling. Specify negative one (-1) milliseconds to disable periodic signaling.
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Watcher(TimeSpan, TimeSpan)

Initializes a new instance of the Watcher class.

Declaration
protected Watcher(TimeSpan dueTime, TimeSpan period)
Parameters
Type Name Description
System.TimeSpan dueTime

A System.TimeSpan representing the amount of time to delay before the Watcher starts signaling. Specify negative one (-1) milliseconds to prevent the signaling from starting. Specify zero (0) to start the signaling immediately.
System.TimeSpan period

The time interval between periodic signaling. Specify negative one (-1) milliseconds to disable periodic signaling.
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Watcher(TimeSpan, TimeSpan, TimeSpan)

Initializes a new instance of the Watcher class.

Declaration
protected Watcher(TimeSpan dueTime, TimeSpan period, TimeSpan dueTimeOnChanged)
Parameters
Type Name Description
System.TimeSpan dueTime

A System.TimeSpan representing the amount of time to delay before the Watcher starts signaling. Specify negative one (-1) milliseconds to prevent the signaling from starting. Specify zero (0) to start the signaling immediately.
System.TimeSpan period

The time interval between periodic signaling. Specify negative one (-1) milliseconds to disable periodic signaling.
System.TimeSpan dueTimeOnChanged

The amount of time to postpone a Changed event. Specify zero (0) to disable postponing.

Properties

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DueTime

Gets or sets the System.TimeSpan representing the amount of time to delay before the Watcher starts signaling.

Declaration
protected TimeSpan DueTime { get; }
Property Value
Type Description
System.TimeSpan

A System.TimeSpan representing the amount of time to delay before the Watcher starts signaling.
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DueTimeOnChanged

Gets the amount of time to postpone a Changed event.

Declaration
protected TimeSpan DueTimeOnChanged { get; }
Property Value
Type Description
System.TimeSpan
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Period

Gets the time interval between periodic signaling.

Declaration
protected TimeSpan Period { get; }
Property Value
Type Description
System.TimeSpan

A System.TimeSpan representing the time interval between periodic signaling.
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UtcLastModified

Gets time when the resource being monitored was last changed.

Declaration
public DateTime UtcLastModified { get; }
Property Value
Type Description
System.DateTime

The time when the resource being monitored was last changed.
Remarks

This property is measured in Coordinated Universal Time (UTC) (also known as Greenwich Mean Time).

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UtcLastSignaled

Gets the time when the last signaling occurred.

Declaration
public DateTime UtcLastSignaled { get; }
Property Value
Type Description
System.DateTime

The time when the last signaling occurred.
Remarks

This property is measured in Coordinated Universal Time (UTC) (also known as Greenwich Mean Time).

Methods

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ChangeSignaling(TimeSpan)

Changes the signaling timer of the Watcher.

Declaration
public void ChangeSignaling(TimeSpan dueTime)
Parameters
Type Name Description
System.TimeSpan dueTime

A System.TimeSpan representing the amount of time to delay before the Watcher starts signaling. Specify negative one (-1) milliseconds to prevent the signaling from starting. Specify zero (0) to start the signaling immediately.
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ChangeSignaling(TimeSpan, TimeSpan)

Changes the signaling timer of the Watcher.

Declaration
public virtual void ChangeSignaling(TimeSpan dueTime, TimeSpan period)
Parameters
Type Name Description
System.TimeSpan dueTime

A System.TimeSpan representing the amount of time to delay before the Watcher starts signaling. Specify negative one (-1) milliseconds to prevent the signaling from starting. Specify zero (0) to start the signaling immediately.
System.TimeSpan period

The time interval between periodic signaling. Specify negative one (-1) milliseconds to disable periodic signaling.
Remarks

If dueTime is zero (0), the signaling is started immediately. If dueTime is negative one (-1) milliseconds, the signaling is never started; and the underlying timer is disabled, but can be re-enabled by specifying a positive value for dueTime. If period is zero (0) or negative one (-1) milliseconds, and dueTime is positive, the signaling is done once; the periodic behavior of the underlying timer is disabled, but can be re-enabled by specifying a value greater than zero for period.

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Dispose()

Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.

Declaration
public void Dispose()
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Dispose(Boolean)

Releases unmanaged and - optionally - managed resources.

Declaration
protected virtual void Dispose(bool disposing)
Parameters
Type Name Description
System.Boolean disposing

true to release both managed and unmanaged resources; false to release only unmanaged resources.
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HandleSignaling()

Handles the signaling of this Watcher.

Declaration
protected abstract void HandleSignaling()
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OnChangedRaised()

Raises the Changed event.

Declaration
protected void OnChangedRaised()
Remarks

This method raises the Changed event with UtcLastModified and DueTimeOnChanged passed to a new instance of WatcherEventArgs.

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OnChangedRaised(WatcherEventArgs)

Raises the Changed event.

Declaration
protected virtual void OnChangedRaised(WatcherEventArgs e)
Parameters
Type Name Description
WatcherEventArgs e

The WatcherEventArgs instance containing the event data.
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SetUtcLastModified(DateTime)

Marks the time when a resource being monitored was last changed.

Declaration
protected void SetUtcLastModified(DateTime utcLastModified)
Parameters
Type Name Description
System.DateTime utcLastModified

The time when a resource being monitored was last changed.

Events

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Changed

Occurs when a resource has changed.

Declaration
public event EventHandler<WatcherEventArgs> Changed
Event Type
Type Description
System.EventHandler<WatcherEventArgs>

Implements

System.IDisposable

Extension Methods