EventLog.GetEventLogs Method

Definition

Namespace:

System.Diagnostics

Assembly:

System.Diagnostics.EventLog.dll

Creates an array of the event logs.

Overloads

GetEventLogs(String)	Searches for all event logs on the given computer and creates an array of EventLog objects that contain the list.
GetEventLogs()	Searches for all event logs on the local computer and creates an array of EventLog objects that contain the list.

GetEventLogs(String)

Source:

EventLog.cs

Searches for all event logs on the given computer and creates an array of EventLog objects that contain the list.

public:
 static cli::array <System::Diagnostics::EventLog ^> ^ GetEventLogs(System::String ^ machineName);

public static System.Diagnostics.EventLog[] GetEventLogs (string machineName);

static member GetEventLogs : string -> System.Diagnostics.EventLog[]

Public Shared Function GetEventLogs (machineName As String) As EventLog()

Parameters

machineName

String

The computer on which to search for event logs.

Returns

EventLog[]

An array of type EventLog that represents the logs on the given computer.

Exceptions

ArgumentException

The machineName parameter is an invalid computer name.

InvalidOperationException

You do not have read access to the registry.

-or-

There is no event log service on the computer.

Examples

The following example gets a list of logs on the computer "myServer". It then outputs the name of each log.

#using <System.dll>

using namespace System;
using namespace System::Diagnostics;
using namespace System::Threading;
int main()
{
   array<EventLog^>^remoteEventLogs;
   remoteEventLogs = EventLog::GetEventLogs( "myServer" );
   Console::WriteLine( "Number of logs on computer: {0}", remoteEventLogs->Length );
   System::Collections::IEnumerator^ myEnum = remoteEventLogs->GetEnumerator();
   while ( myEnum->MoveNext() )
   {
      EventLog^ log = safe_cast<EventLog^>(myEnum->Current);
      Console::WriteLine( "Log: {0}", log->Log );
   }
}

using System;
using System.Diagnostics;

class MySample
{
    public static void Main()
    {
        EventLog[] remoteEventLogs;

        remoteEventLogs = EventLog.GetEventLogs("myServer");

        Console.WriteLine("Number of logs on computer: " + remoteEventLogs.Length);

        foreach (EventLog log in remoteEventLogs)
        {
            Console.WriteLine("Log: " + log.Log);
        }
    }
}

Imports System.Diagnostics
Imports System.Threading

Class MySample
    Public Shared Sub Main()
        Dim remoteEventLogs() As EventLog
        
        remoteEventLogs = EventLog.GetEventLogs("myServer")
        
        Console.WriteLine(("Number of logs on computer: " & remoteEventLogs.Length))
        
        Dim log As EventLog
        For Each log In  remoteEventLogs
            Console.WriteLine(("Log: " & log.Log))
        Next log
    End Sub
End Class

Remarks

The array of EventLog objects is a snapshot of all event logs on the computer specified by the machineName parameter when the call to GetEventLogs is made. This is not a dynamic collection, so it does not reflect the deletion or creation of logs in real time. You should verify that a log in the array exists before you read or write to it. The array usually includes at least three logs: Application, System, and Security. If you created custom logs on the specified computer, they will appear in the array as well.

GetEventLogs is a static method, so it can be called on the EventLog class itself. It is not necessary to create an instance of an EventLog object to make a call to the method.

To retrieve the list of event logs, you must have the appropriate registry permissions. These permissions are identical to those required to call Exists and SourceExists.

See also

• Exists(String)
• Log
• MachineName

GetEventLogs()

Source:

EventLog.cs

Searches for all event logs on the local computer and creates an array of EventLog objects that contain the list.

public:
 static cli::array <System::Diagnostics::EventLog ^> ^ GetEventLogs();

public static System.Diagnostics.EventLog[] GetEventLogs ();

static member GetEventLogs : unit -> System.Diagnostics.EventLog[]

Public Shared Function GetEventLogs () As EventLog()

Returns

EventLog[]

An array of type EventLog that represents the logs on the local computer.

Exceptions

SystemException

You do not have read access to the registry.

-or-

There is no event log service on the computer.

Examples

The following example enumerates the event logs defined on the local computer, and displays configuration details for each event log.

void DisplayEventLogProperties()
{
   
   // Iterate through the current set of event log files,
   // displaying the property settings for each file.
   array<EventLog^>^eventLogs = EventLog::GetEventLogs();
   System::Collections::IEnumerator^ myEnum = eventLogs->GetEnumerator();
   while ( myEnum->MoveNext() )
   {
      EventLog^ e = safe_cast<EventLog^>(myEnum->Current);
      Int64 sizeKB = 0;
      Console::WriteLine();
      Console::WriteLine( "{0}:", e->LogDisplayName );
      Console::WriteLine( "  Log name = \t\t {0}", e->Log );
      Console::WriteLine( "  Number of event log entries = {0}", e->Entries->Count );
      
      // Determine if there is a file for this event log.
      RegistryKey ^ regEventLog = Registry::LocalMachine->OpenSubKey( String::Format( "System\\CurrentControlSet\\Services\\EventLog\\{0}", e->Log ) );
      if ( regEventLog )
      {
         Object^ temp = regEventLog->GetValue( "File" );
         if ( temp != nullptr )
         {
            Console::WriteLine( "  Log file path = \t {0}", temp );
            FileInfo^ file = gcnew FileInfo( temp->ToString() );
            
            // Get the current size of the event log file.
            if ( file->Exists )
            {
               sizeKB = file->Length / 1024;
               if ( (file->Length % 1024) != 0 )
               {
                  sizeKB++;
               }
               Console::WriteLine( "  Current size = \t {0} kilobytes", sizeKB );
            }
         }
         else
         {
            Console::WriteLine( "  Log file path = \t <not set>" );
         }
      }
      
      // Display the maximum size and overflow settings.
      sizeKB = e->MaximumKilobytes;
      Console::WriteLine( "  Maximum size = \t {0} kilobytes", sizeKB );
      Console::WriteLine( "  Overflow setting = \t {0}", e->OverflowAction );
      switch ( e->OverflowAction )
      {
         case OverflowAction::OverwriteOlder:
            Console::WriteLine( "\t Entries are retained a minimum of {0} days.", e->MinimumRetentionDays );
            break;

         case OverflowAction::DoNotOverwrite:
            Console::WriteLine( "\t Older entries are not overwritten." );
            break;

         case OverflowAction::OverwriteAsNeeded:
            Console::WriteLine( "\t If number of entries equals max size limit, a new event log entry overwrites the oldest entry." );
            break;

         default:
            break;
      }
   }
}

static void DisplayEventLogProperties()
{
    // Iterate through the current set of event log files,
    // displaying the property settings for each file.

    EventLog[] eventLogs = EventLog.GetEventLogs();
    foreach (EventLog e in eventLogs)
    {
        Int64 sizeKB = 0;

        Console.WriteLine();
        Console.WriteLine("{0}:", e.LogDisplayName);
        Console.WriteLine("  Log name = \t\t {0}", e.Log);

        Console.WriteLine("  Number of event log entries = {0}", e.Entries.Count.ToString());

        // Determine if there is an event log file for this event log.
        RegistryKey regEventLog = Registry.LocalMachine.OpenSubKey("System\\CurrentControlSet\\Services\\EventLog\\" + e.Log);
        if (regEventLog != null)
        {
            Object temp = regEventLog.GetValue("File");
            if (temp != null)
            {
                Console.WriteLine("  Log file path = \t {0}", temp.ToString());
                FileInfo file = new FileInfo(temp.ToString());

                // Get the current size of the event log file.
                if (file.Exists)
                {
                    sizeKB = file.Length / 1024;
                    if ((file.Length % 1024) != 0)
                    {
                        sizeKB++;
                    }
                    Console.WriteLine("  Current size = \t {0} kilobytes", sizeKB.ToString());
                }
            }
            else
            {
                Console.WriteLine("  Log file path = \t <not set>");
            }
        }

        // Display the maximum size and overflow settings.

        sizeKB = e.MaximumKilobytes;
        Console.WriteLine("  Maximum size = \t {0} kilobytes", sizeKB.ToString());
        Console.WriteLine("  Overflow setting = \t {0}", e.OverflowAction.ToString());

        switch (e.OverflowAction)
        {
            case OverflowAction.OverwriteOlder:
                Console.WriteLine("\t Entries are retained a minimum of {0} days.",
                    e.MinimumRetentionDays);
                break;
            case OverflowAction.DoNotOverwrite:
                Console.WriteLine("\t Older entries are not overwritten.");
                break;
            case OverflowAction.OverwriteAsNeeded:
                Console.WriteLine("\t If number of entries equals max size limit, a new event log entry overwrites the oldest entry.");
                break;
            default:
                break;
        }
    }
}

Shared Sub DisplayEventLogProperties()

   ' Iterate through the current set of event log files,
   ' displaying the property settings for each file.
   Dim eventLogs As EventLog() = EventLog.GetEventLogs()
   
   Dim e As EventLog
   For Each e In  eventLogs
      Dim sizeKB As Int64 = 0
      
      Console.WriteLine()
      Console.WriteLine("{0}:", e.LogDisplayName)
      Console.WriteLine("  Log name = " + ControlChars.Tab _
                          + ControlChars.Tab + " {0}", e.Log)

      Console.WriteLine("  Number of event log entries = {0}", e.Entries.Count.ToString())
      
      ' Determine if there is an event log file for this event log.
      Dim regEventLog As RegistryKey
      regEventLog = Registry.LocalMachine.OpenSubKey( _
             ("System\CurrentControlSet\Services\EventLog\" + e.Log))

      If Not (regEventLog Is Nothing) Then

         Dim temp As Object = regEventLog.GetValue("File")
         If Not (temp Is Nothing) Then

            Console.WriteLine("  Log file path = " + ControlChars.Tab _
                                  + " {0}", temp.ToString())
            Dim file As New FileInfo(temp.ToString())
            
            ' Get the current size of the event log file.
            If file.Exists Then
               sizeKB = file.Length / 1024
               If file.Length Mod 1024 <> 0 Then
                  sizeKB += 1
               End If
               Console.WriteLine("  Current size = " + ControlChars.Tab _
                          + " {0} kilobytes", sizeKB.ToString())
            End If
         Else
            Console.WriteLine("  Log file path = " + ControlChars.Tab _
                             + " <not set>")
         End If
      End If
      
      ' Display the maximum size and overflow settings.
      sizeKB = e.MaximumKilobytes
      Console.WriteLine("  Maximum size = " + ControlChars.Tab _
                         + " {0} kilobytes", sizeKB.ToString())
      Console.WriteLine("  Overflow setting = " + ControlChars.Tab _
                         + " {0}", e.OverflowAction.ToString())
      
      Select Case e.OverflowAction
         Case OverflowAction.OverwriteOlder
            Console.WriteLine(ControlChars.Tab + _
                 " Entries are retained a minimum of {0} days.", _
                 e.MinimumRetentionDays)
         Case OverflowAction.DoNotOverwrite
            Console.WriteLine(ControlChars.Tab + _
                 " Older entries are not overwritten.")
         Case OverflowAction.OverwriteAsNeeded
            Console.WriteLine(ControlChars.Tab + _
                 " If number of entries equals max size limit, a new event log entry overwrites the oldest entry.")
         Case Else
      End Select

   Next e

End Sub

Remarks

The array of EventLog objects is a snapshot of all event logs on the local computer when the call to GetEventLogs is made. This is not a dynamic collection, so it does not reflect the deletion or creation of logs in real time. You should verify that a log in the array exists before you read or write to it. The array usually includes at least three logs: Application, System, and Security. If you created custom logs on the local computer, they will appear in the array as well.

To retrieve the list of event logs, you must have the appropriate registry permissions. These permissions are identical to those required to call Exists and SourceExists.

See also

• Exists(String)
• Log