.NET Framework Class Library
EventAttribute Class

Specifies additional event schema information for an event.

Inheritance Hierarchy
SystemObject
   SystemAttribute
    System.Diagnostics.TracingEventAttribute

Namespace:   System.Diagnostics.Tracing
Assemblies:   mscorlib (in mscorlib.dll)
  System.Diagnostics.Tracing (in System.Diagnostics.Tracing.dll)
Syntax
<[%$TOPIC/hh393456_en-us_VS_110_2_0_0_0_0%]([%$TOPIC/hh393456_en-us_VS_110_2_0_0_0_1%].Method)> _
Public NotInheritable Class EventAttribute _
	Inherits [%$TOPIC/hh393456_en-us_VS_110_2_0_0_0_2%]
[[%$TOPIC/hh393456_en-us_VS_110_2_0_1_0_0%]([%$TOPIC/hh393456_en-us_VS_110_2_0_1_0_1%].Method)]
public sealed class EventAttribute : [%$TOPIC/hh393456_en-us_VS_110_2_0_1_0_2%]
[[%$TOPIC/hh393456_en-us_VS_110_2_0_2_0_0%]([%$TOPIC/hh393456_en-us_VS_110_2_0_2_0_1%]::Method)]
public ref class EventAttribute sealed : public [%$TOPIC/hh393456_en-us_VS_110_2_0_2_0_2%]
[<[%$TOPIC/hh393456_en-us_VS_110_2_0_3_0_0%]>]
[<[%$TOPIC/hh393456_en-us_VS_110_2_0_3_0_1%]([%$TOPIC/hh393456_en-us_VS_110_2_0_3_0_2%].Method)>]
type EventAttribute =  
    class 
        inherit [%$TOPIC/hh393456_en-us_VS_110_2_0_3_0_3%] 
    end
public final class EventAttribute extends [%$TOPIC/hh393456_en-us_VS_110_2_0_4_0_0%]

The EventAttribute type exposes the following members.

Constructors
  NameDescription
Public method EventAttributeInitializes a new instance of the EventAttribute class with the specified event identifier.
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Properties
  NameDescription
Public property ActivityOptionsSpecifies 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.
Public property ChannelGets or sets an additional event log where the event should be written.
Public property EventIdGets or sets the identifier for the event.
Public property KeywordsGets or sets the keywords for the event.
Public property LevelGets or sets the level for the event.
Public property MessageGets or sets the message for the event.
Public property OpcodeGets or sets the operation code for the event.
Public property TagsGets and 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.
Public property TaskGets or sets the task for the event.
Public property TypeIdWhen implemented in a derived class, gets a unique identifier for this Attribute. (Inherited from Attribute.)
Public property VersionGets or sets the version of the event.
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Methods
  NameDescription
Public method EqualsInfrastructure. Returns a value that indicates whether this instance is equal to a specified object. (Inherited from Attribute.)
Public method GetHashCodeReturns the hash code for this instance. (Inherited from Attribute.)
Public method GetTypeGets the Type of the current instance. (Inherited from Object.)
Public method IsDefaultAttributeWhen overridden in a derived class, indicates whether the value of this instance is the default value for the derived class. (Inherited from Attribute.)
Public method MatchWhen overridden in a derived class, returns a value that indicates whether this instance equals a specified object. (Inherited from Attribute.)
Public method ToStringReturns a string that represents the current object. (Inherited from Object.)
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Explicit Interface Implementations
  NameDescription
Explicit interface implemetation Private method _AttributeGetIDsOfNamesMaps a set of names to a corresponding set of dispatch identifiers. (Inherited from Attribute.)
Explicit interface implemetation Private method _AttributeGetTypeInfoRetrieves the type information for an object, which can be used to get the type information for an interface. (Inherited from Attribute.)
Explicit interface implemetation Private method _AttributeGetTypeInfoCountRetrieves the number of type information interfaces that an object provides (either 0 or 1). (Inherited from Attribute.)
Explicit interface implemetation Private method _AttributeInvokeProvides access to properties and methods exposed by an object. (Inherited from Attribute.)
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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.

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 Sub Failure(ByVal message As String)
    WriteEvent(1, message)
End Sub 'Failure
[Event(1, Message = "Application Failure: {0}", Level = EventLevel.Error, Keywords = Keywords.Diagnostic)]
public void Failure(string message) { WriteEvent(1, message); }
<[Event](2, Message:="Starting up.", Keywords:=Keywords.Perf, Level:=EventLevel.Informational)> _
Public Sub Startup()
    WriteEvent(2)
End Sub 'Startup
[Event(2, Message = "Starting up.", Keywords = Keywords.Perf, Level = EventLevel.Informational)]
public void Startup() { WriteEvent(2); }
<[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 'PageStart
[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](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 'PageStop
[Event(4, Opcode = EventOpcode.Stop, Task = Tasks.Page, Keywords = Keywords.Page, Level = EventLevel.Informational)]
public void PageStop(int ID) { if (IsEnabled()) WriteEvent(4, ID); }
Version Information

.NET Framework

Supported in: 4.6, 4.5

.NET for Windows Phone apps

Supported in: Windows Phone 8.1
Thread Safety
Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.