EventAttribute Class

Definition

Namespace:

System.Diagnostics.Tracing

Assembly:

System.Diagnostics.Tracing.dll

Source:

EventSource.cs

Specifies additional event schema information for an event.

public ref class EventAttribute sealed : Attribute

[System.AttributeUsage(System.AttributeTargets.Method)]
public sealed class EventAttribute : Attribute

[<System.AttributeUsage(System.AttributeTargets.Method)>]
type EventAttribute = class
    inherit Attribute

Public NotInheritable Class EventAttribute
Inherits Attribute

Inheritance

Object

Attribute

EventAttribute

Attributes

AttributeUsageAttribute

Examples

The following example shows how to use the EventAttribute class to define a variety of events. This code example is part of a larger example provided for the EventSource class.

[Event(1, Message = "Application Failure: {0}", Level = EventLevel.Error, Keywords = Keywords.Diagnostic)]
public void Failure(string message) { WriteEvent(1, message); }

<[Event](1, Message:="Application Failure: {0}", Level:=EventLevel.Error, Keywords:=Keywords.Diagnostic)> _
Public Sub Failure(ByVal message As String)
    WriteEvent(1, message)
End Sub

[Event(2, Message = "Starting up.", Keywords = Keywords.Perf, Level = EventLevel.Informational)]
public void Startup() { WriteEvent(2); }

<[Event](2, Message:="Starting up.", Keywords:=Keywords.Perf, Level:=EventLevel.Informational)> _
Public Sub Startup()
    WriteEvent(2)
End Sub

[Event(3, Message = "loading page {1} activityID={0}", Opcode = EventOpcode.Start,
    Task = Tasks.Page, Keywords = Keywords.Page, Level = EventLevel.Informational)]
public void PageStart(int ID, string url) { if (IsEnabled()) WriteEvent(3, ID, url); }

<[Event](3, Message:="loading page {1} activityID={0}", Opcode:=EventOpcode.Start, Task:=Tasks.Page, Keywords:=Keywords.Page, Level:=EventLevel.Informational)> _
Public Sub PageStart(ByVal ID As Integer, ByVal url As String)
    If IsEnabled() Then
        WriteEvent(3, ID, url)
    End If
End Sub

[Event(4, Opcode = EventOpcode.Stop, Task = Tasks.Page, Keywords = Keywords.Page, Level = EventLevel.Informational)]
public void PageStop(int ID) { if (IsEnabled()) WriteEvent(4, ID); }

<[Event](4, Opcode:=EventOpcode.Stop, Task:=Tasks.Page, Keywords:=Keywords.Page, Level:=EventLevel.Informational)> _
Public Sub PageStop(ByVal ID As Integer)
    If IsEnabled() Then
        WriteEvent(4, ID)
    End If
End Sub

Remarks

When you apply this attribute to an ETW event method defined on an EventSource-derived class, you must call the WriteEvent method on the base class, passing the event ID, followed by the same arguments as the defined method is passed. You should follow the pattern shown in the following examples.

Constructors

EventAttribute(Int32)

Initializes a new instance of the EventAttribute class with the specified event identifier.

Properties

ActivityOptions	Specifies the behavior of the start and stop events of an activity. An activity is the region of time in an app between the start and the stop.
Channel	Gets or sets an additional event log where the event should be written.
EventId	Gets or sets the identifier for the event.
Keywords	Gets or sets the keywords for the event.
Level	Gets or sets the level for the event.
Message	Gets or sets the message for the event.
Opcode	Gets or sets the operation code for the event.
Tags	Gets or sets the EventTags value for this EventAttribute object. An event tag is a user-defined value that is passed through when the event is logged.
Task	Gets or sets the task for the event.
TypeId	When implemented in a derived class, gets a unique identifier for this Attribute. (Inherited from Attribute)
Version	Gets or sets the version of the event.

Methods

Equals(Object)	Returns a value that indicates whether this instance is equal to a specified object. (Inherited from Attribute)
GetHashCode()	Returns the hash code for this instance. (Inherited from Attribute)
GetType()	Gets the Type of the current instance. (Inherited from Object)
IsDefaultAttribute()	When overridden in a derived class, indicates whether the value of this instance is the default value for the derived class. (Inherited from Attribute)
Match(Object)	When overridden in a derived class, returns a value that indicates whether this instance equals a specified object. (Inherited from Attribute)
MemberwiseClone()	Creates a shallow copy of the current Object. (Inherited from Object)
ToString()	Returns a string that represents the current object. (Inherited from Object)