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WebBaseEvent Class

Defines the base class for the ASP.NET health-monitoring events.

Namespace:  System.Web.Management
Assembly:  System.Web (in System.Web.dll)

<AspNetHostingPermissionAttribute(SecurityAction.LinkDemand, Level := AspNetHostingPermissionLevel.Minimal)> _
<AspNetHostingPermissionAttribute(SecurityAction.InheritanceDemand, Level := AspNetHostingPermissionLevel.Minimal)> _
Public Class WebBaseEvent
Dim instance As WebBaseEvent

ASP.NET health monitoring allows production and operations staff to manage deployed Web applications. The System.Web.Management namespace contains the health-event types responsible for packaging application health-status data and the provider types responsible for processing this data. It also contains supporting types that help during the management of health events.

The WebBaseEvent class is the root of the inheritance tree for all the ASP.NET health-monitoring event types. It uses the WebApplicationInformation class to obtain application information that is available to its derived class.


In most cases you will be able to use the ASP.NET health-monitoring types as implemented, and you will control the health-monitoring system by specifying values in the <healthMonitoring> configuration section. You can also derive from the health-monitoring types to create your own custom events and providers. For an example of deriving from the WebBaseEvent class, see the example provided in this topic.

Notes to Inheritors:

When you format your custom event information for display, override the FormatCustomEventDetails method rather than the ToString method. This will avoid overwriting or tampering with sensitive system information.

The event code you specify for your custom event must be greater than WebExtendedBase.

The following example shows how to derive from the WebBaseEvent class to create a custom health-monitoring event.

Imports System
Imports System.Text
Imports System.Web
Imports System.Web.Management

Public Class SampleWebBaseEvent
    Inherits System.Web.Management.WebBaseEvent
    Implements System.Web.Management.IWebEventCustomEvaluator

    Private customCreatedMsg, customRaisedMsg As String 

    ' Store firing record info. 
    Private Shared firingRecordInfo As String 

    ' Implements the IWebEventCustomEvaluator.CanFire  
    ' method. It is called by the ASP.NET if this custom 
    ' type is configured in the profile 
    ' element of the healthMonitoring section. 
    Public Function CanFire( _
    ByVal e As System.Web.Management.WebBaseEvent, _
    ByVal rule As RuleFiringRecord) As Boolean _
    Implements System.Web.Management.IWebEventCustomEvaluator.CanFire

        Dim fireEvent As Boolean 
        Dim lastFired As String = _
        Dim timesRaised As String = _

        ' Fire every other event raised.
        fireEvent = _
        IIf(rule.TimesRaised Mod 2 = 0, True, False)

        If fireEvent Then
            firingRecordInfo = String.Format( _
            "Event last fired: {0}", lastFired) + _
            String.Format( _
            ". Times raised: {0}",  timesRaised) 

            firingRecordInfo = String.Format( _
            "Event not fired. Times raised: {0}", _
        End If 

        Return fireEvent

    End Function 'CanFire

    ' Invoked in case of events identified only by  
    ' their event code. 
    Public Sub New(ByVal msg As String, _
    ByVal eventSource As Object, _
    ByVal eventCode As Integer)
        MyBase.New(msg, eventSource, eventCode)
        ' Perform custom initialization.
        customCreatedMsg = String.Format( _
        "Event created at: {0}", DateTime.Now.TimeOfDay.ToString())

    End Sub 'New 

    ' Invoked in case of events identified by their  
    ' event code.and related event detailed code. 
    Public Sub New(ByVal msg As String, _
    ByVal eventSource As Object, _
    ByVal eventCode As Integer, _
    ByVal eventDetailCode As Integer)
        MyBase.New(msg, eventSource, _
        eventCode, eventDetailCode)
        ' Perform custom initialization.
        customCreatedMsg = String.Format( _
        "Event created at: {0}", DateTime.Now.TimeOfDay.ToString())

    End Sub 'New 

    ' Raises the SampleWebBaseEvent. 
    Public Overrides Sub Raise()
        ' Perform custom processing. 
        customRaisedMsg = String.Format( _
        "Event raised at: {0}", DateTime.Now.TimeOfDay.ToString())

        ' Raise the event. 

    End Sub 'Raise

    ' Raises the SampleWebBaseEvent. 
    Public Sub CustomRaise(ByVal evnt _
    As System.Web.Management.WebBaseEvent)

        ' Raise the event.

    End Sub 'CustomRaise

    ' Gets the event code. 
    Public Function GetEventCode(ByVal detail _
    As Boolean) As Integer 
        Dim eCode As Integer 

        If Not detail Then 
            ' Get the event code.
            eCode = EventCode
            ' Get the detail event code. 
            eCode = EventDetailCode
        End If 
        Return eCode

    End Function 'GetEventCode

    ' Gets the event sequence. 
    Public Function GetEventSequence() As Long
        ' Get the event sequence. 
        Dim eventSequence As Long = eventSequence
        Return eventSequence

    End Function 'GetEventSequence

    ' Gets the event source. 
    Public Function GetEventSource() As [Object]
        ' Get the event source. 
        Dim [source] As [Object] = Me.EventSource
        Return [source]

    End Function 'GetEventSource

    ' Gets the event time. 
    Public Function GetEventTime() As DateTime
        ' Get the event source. 
        Dim eTime As DateTime = EventTime
        Return eTime

    End Function 'GetEventTime

    ' Gets the event time. 
    Public Function GetEventTimeUtc() As DateTime
        ' Get the event source. 
        Dim eTime As DateTime = EventTimeUtc
        Return eTime

    End Function 'GetEventTimeUtc

    ' Gets the event sequence. 
    Public Function GetEventMessage() As String 
        ' Get the event message. 
        Dim eventMsg As String = Message
        Return eventMsg

    End Function 'GetEventMessage

    ' Gets the current application information. 
    Public Function GetEventAppInfo() As WebApplicationInformation
        ' Get the event message. 
        Dim appImfo As WebApplicationInformation = _
        Return appImfo

    End Function 'GetEventAppInfo

    ' Implements the ToString() method. 
    Public Overrides Function ToString() As String 
        Return MyBase.ToString()

    End Function 'ToString

    ' Implements the ToString(bool, bool) method. 
    Public Function customToString(ByVal includeAppInfo As Boolean, _
    ByVal includeCustomInfo As Boolean) As String 
        Return MyBase.ToString(includeAppInfo, includeCustomInfo)

    End Function 'customToString

    ' Gets the event identifier. 
    Public Function GetEventId() As Guid
        Dim evId As Guid = EventID
        Return evId

    End Function 'GetEventId

    'Formats Web request event information. 
    Public Overrides Sub FormatCustomEventDetails( _
ByVal formatter As WebEventFormatter)

        ' Add custom data.

        formatter.IndentationLevel += 1

        formatter.TabSize = 4

        formatter.AppendLine("*SampleWebBaseEvent Start *")
        formatter.AppendLine("Custom information goes here")
        formatter.AppendLine("* SampleWebBaseEvent End *")
        ' Display custom event timing.
        formatter.IndentationLevel -= 1

    End Sub 'FormatCustomEventDetails

End Class 'SampleWebBaseEvent

The following example is an excerpt of the configuration file that enables ASP.NET to use the custom event.

<healthMonitoring enabled="true" heartBeatInterval="0">
    <add  name="SampleWebBaseEvent" 
      webbaseevent, Version=1.0.1573.24438, Culture=neutral, 
      processorArchitecture=MSIL" />


Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0, 2.0