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EventLog.MinimumRetentionDays Property

Gets the number of days to retain entries in the event log.

Namespace:  System.Diagnostics
Assembly:  System (in System.dll)

'Declaration
<ComVisibleAttribute(False)> _
<BrowsableAttribute(False)> _
Public ReadOnly Property MinimumRetentionDays As Integer
'Usage
Dim instance As EventLog 
Dim value As Integer 

value = instance.MinimumRetentionDays

Property Value

Type: System.Int32
The number of days that entries in the event log are retained. The default value is 7.

Use the MinimumRetentionDays property to examine the current setting for an event log. Use ModifyOverflowPolicy to change the minimum number of days that each entry in the event log must be retained.

The MinimumRetentionDays value depends on the configured overflow behavior of the event log. If the OverflowAction property for an event log is set to OverwriteAsNeeded, then the MinimumRetentionDays value is 0. If the OverflowAction property for an event log is set to DoNotOverwrite, then the MinimumRetentionDays value is -1. If the OverflowAction property for an event log is set to OverwriteOlder, then the MinimumRetentionDays value is greater than zero, and represents the number of days to retain event log entries when the event log is full.

The overflow behavior only occurs when an event log reaches its size limit. When an EventLog has its OverflowAction set to OverwriteOlder, and the event log reaches its maximum size, then new entries are written only if they can replace entries whose age exceeds the MinimumRetentionDays period. Retaining event entries for a minimum period is appropriate when the event log is archived regularly. Otherwise, you risk losing new entries when the event log reaches its limit. To avoid losing new event information, set the minimum retention days for events based on your archive schedule for a particular event log.

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

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

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

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