EventLog.EntryWritten Event

Definition

Namespace:

System.Diagnostics

Assembly:

System.Diagnostics.EventLog.dll

Source:

EventLog.cs

Occurs when an entry is written to an event log on the local computer.

public:
 event System::Diagnostics::EntryWrittenEventHandler ^ EntryWritten;

public event System.Diagnostics.EntryWrittenEventHandler EntryWritten;

member this.EntryWritten : System.Diagnostics.EntryWrittenEventHandler 

Public Custom Event EntryWritten As EntryWrittenEventHandler 

Event Type

EntryWrittenEventHandler

Examples

The following example handles an entry written event.

#using <System.dll>

using namespace System;
using namespace System::Diagnostics;
using namespace System::Threading;
ref class MySample
{
private:

   // This member is used to wait for events.
   static AutoResetEvent^ signal;

public:
   static void main()
   {
      signal = gcnew AutoResetEvent( false );
      EventLog^ myNewLog = gcnew EventLog;
      myNewLog->Source = "testEventLogEvent";
      myNewLog->EntryWritten += gcnew EntryWrittenEventHandler( MyOnEntryWritten );
      myNewLog->EnableRaisingEvents = true;
      myNewLog->WriteEntry("Test message", EventLogEntryType::Information);
      signal->WaitOne();
   }

   static void MyOnEntryWritten( Object^ /*source*/, EntryWrittenEventArgs^ /*e*/ )
   {
      Console::WriteLine("In event handler");
      signal->Set();
   }

};

int main()
{
   MySample::main();
}

using System;
using System.Diagnostics;
using System.Threading;

class MySample{

    // This member is used to wait for events.
    static AutoResetEvent signal;

    public static void Main(){

        signal = new AutoResetEvent(false);
        EventLog myNewLog = new EventLog("Application", ".", "testEventLogEvent");

        myNewLog.EntryWritten += new EntryWrittenEventHandler(MyOnEntryWritten);
        myNewLog.EnableRaisingEvents = true;
        myNewLog.WriteEntry("Test message", EventLogEntryType.Information);
        signal.WaitOne();
    }

    public static void MyOnEntryWritten(object source, EntryWrittenEventArgs e){
        Console.WriteLine("In event handler");
        signal.Set();
    }
}

Option Explicit On 
Option Strict On

Imports System.Diagnostics
Imports System.Threading


Class MySample

    ' This member is used to wait for events.
    Private Shared signal As AutoResetEvent


    Public Shared Sub Main()

        signal = New AutoResetEvent(False)
        Dim myNewLog As New EventLog("Application", ".", "testEventLogEvent")

        AddHandler myNewLog.EntryWritten, AddressOf MyOnEntryWritten
        myNewLog.EnableRaisingEvents = True
        myNewLog.WriteEntry("Test message", EventLogEntryType.Information)

        signal.WaitOne()
    End Sub


    Public Shared Sub MyOnEntryWritten(ByVal [source] As Object, ByVal e As EntryWrittenEventArgs)
        Console.WriteLine("In event handler")
        signal.Set()
    End Sub
End Class

Remarks

To get event notifications, you must set EnableRaisingEvents to true. You can only receive event notifications when entries are written on the local computer. You cannot receive notifications for entries written on remote computers.

When you create an EntryWritten delegate, you identify the method that will handle the event. To associate the event with your event handler, add an instance of the delegate to the event. The event handler is called whenever the event occurs, until you remove the delegate. For more information about handling events with delegates, see Handling and Raising Events.

The system responds to WriteEntry only if the last write event occurred at least six seconds previously. This implies you will only receive one EntryWritten event notification within a six-second interval, even if more than one event log change occurs. If you insert a sufficiently long sleep interval (around 10 seconds) between calls to WriteEntry, you are less likely to miss an event. However, if write events occur more frequently, you might not receive the event notification until the next interval. Typically, missed event notifications are not lost, but delayed.

See also

• EnableRaisingEvents