FileRecordSequence Classe

Definizione

public ref class FileRecordSequence sealed : IDisposable, System::IO::Log::IRecordSequence

public sealed class FileRecordSequence : IDisposable, System.IO.Log.IRecordSequence

type FileRecordSequence = class
    interface IRecordSequence
    interface IDisposable

Public NotInheritable Class FileRecordSequence
Implements IDisposable, IRecordSequence

Ereditarietà

Object

FileRecordSequence

Implementazioni

IDisposable IRecordSequence

Esempio

Nell'esempio seguente viene creata una sequenza di record, vi vengono aggiunti record che vengono quindi letti.

public class MyLog
{
    string logName = "test.log";
    FileRecordSequence sequence = null;
    bool delete = true;

    public MyLog()
    {
    // Create a FileRecordSequence.
        sequence = new FileRecordSequence(logName, FileAccess.ReadWrite);
    }

// Append records to the record sequence.
    public void AppendRecords()
    {
        Console.WriteLine("Appending Log Records...");
        SequenceNumber previous = SequenceNumber.Invalid;

        previous = sequence.Append(CreateData("Hello World!"), SequenceNumber.Invalid, SequenceNumber.Invalid, RecordAppendOptions.ForceFlush);
        previous = sequence.Append(CreateData("This is my first Logging App"), SequenceNumber.Invalid, SequenceNumber.Invalid, RecordAppendOptions.ForceFlush);
        previous = sequence.Append(CreateData("Using FileRecordSequence..."), SequenceNumber.Invalid, SequenceNumber.Invalid, RecordAppendOptions.ForceFlush);

        Console.WriteLine("Done...");
    }
    
// Read the records added to the log.
    public void ReadRecords()
    {
        Encoding enc = Encoding.Unicode;

        Console.WriteLine();

        Console.WriteLine("Reading Log Records...");
        try
        {
            foreach (LogRecord record in this.sequence.ReadLogRecords(this.sequence.BaseSequenceNumber, LogRecordEnumeratorType.Next))
            {
                byte[] data = new byte[record.Data.Length];
                record.Data.Read(data, 0, (int)record.Data.Length);
                string mystr = enc.GetString(data);
                Console.WriteLine("    {0}", mystr);
            }
        }
        catch (Exception e)
        {
            Console.WriteLine("Exception {0} {1}", e.GetType(), e.Message);
        }

        Console.WriteLine();
    }

// Dispose the record sequence and delete the log file.
    public void Cleanup()
    {
    // Dispose the sequence.
        sequence.Dispose();

    // Delete the log file.
        if (delete)
        {
            try
            {
                File.Delete(this.logName);
            }
            catch (Exception e)
            {
                Console.WriteLine("Exception {0} {1}", e.GetType(), e.Message);
            }
        }
    }

// Converts the given data to an Array of ArraySegment<byte>
    public static IList<ArraySegment<byte>> CreateData(string str)
    {
        Encoding enc = Encoding.Unicode;

        byte[] array = enc.GetBytes(str);

        ArraySegment<byte>[] segments = new ArraySegment<byte>[1];
        segments[0] = new ArraySegment<byte>(array);

        return Array.AsReadOnly<ArraySegment<byte>>(segments);
    }
}

class LogSample
{
    static void Main2(string[] args)
    {
        MyLog log = new MyLog();

        log.AppendRecords();
        log.ReadRecords();
        log.Cleanup();
    }
}

Public Class MyLog
    Private logName As String = "test.log"
    Private sequence As FileRecordSequence = Nothing
    Private delete As Boolean = True

    Public Sub New()
    ' Create a FileRecordSequence.
        sequence = New FileRecordSequence(logName, FileAccess.ReadWrite)
    End Sub

' Append records to the record sequence.
    Public Sub AppendRecords()
        Console.WriteLine("Appending Log Records...")
        Dim previous As SequenceNumber = SequenceNumber.Invalid

        previous = sequence.Append(CreateData("Hello World!"), SequenceNumber.Invalid, SequenceNumber.Invalid, RecordAppendOptions.ForceFlush)
        previous = sequence.Append(CreateData("This is my first Logging App"), SequenceNumber.Invalid, SequenceNumber.Invalid, RecordAppendOptions.ForceFlush)
        previous = sequence.Append(CreateData("Using FileRecordSequence..."), SequenceNumber.Invalid, SequenceNumber.Invalid, RecordAppendOptions.ForceFlush)

        Console.WriteLine("Done...")
    End Sub

' Read the records added to the log. 
    Public Sub ReadRecords()
        Dim enc As Encoding = Encoding.Unicode

        Console.WriteLine()

        Console.WriteLine("Reading Log Records...")
        Try
            For Each record In Me.sequence.ReadLogRecords(Me.sequence.BaseSequenceNumber, LogRecordEnumeratorType.Next)
                Dim data(record.Data.Length - 1) As Byte
                record.Data.Read(data, 0, CInt(Fix(record.Data.Length)))
                Dim mystr As String = enc.GetString(data)
                Console.WriteLine("    {0}", mystr)
            Next record
        Catch e As Exception
            Console.WriteLine("Exception {0} {1}", e.GetType(), e.Message)
        End Try

        Console.WriteLine()
    End Sub

' Dispose the record sequence and delete the log file. 
    Public Sub Cleanup()
    ' Dispose the sequence.
        sequence.Dispose()

    ' Delete the log file.
        If delete Then
            Try
                File.Delete(Me.logName)
            Catch e As Exception
                Console.WriteLine("Exception {0} {1}", e.GetType(), e.Message)
            End Try
        End If
    End Sub

' Converts the given data to an Array of ArraySegment<byte> 
    Public Shared Function CreateData(ByVal str As String) As IList(Of ArraySegment(Of Byte))
        Dim enc As Encoding = Encoding.Unicode

        Dim array() As Byte = enc.GetBytes(str)

        Dim segments(0) As ArraySegment(Of Byte)
        segments(0) = New ArraySegment(Of Byte)(array)

        Return System.Array.AsReadOnly(Of ArraySegment(Of Byte))(segments)
    End Function
End Class

Friend Class LogSample
    Private Shared Sub Main2(ByVal args() As String)
        Dim log As New MyLog()

        log.AppendRecords()
        log.ReadRecords()
        log.Cleanup()
    End Sub
End Class

Commenti

FileRecordSequence è una sequenza di record basata su un unico file di log nel file system. È una semplice implementazione dell'interfaccia IRecordSequence, in un contesto di semplice log basato su file.

Per modificare un log basato su file, l'account sotto cui è in esecuzione l'applicazione deve disporre di privilegi sufficienti, come imposto dalla sicurezza del file system al momento della costruzione di FileRecordSequence. Inoltre, durante la costruzione viene effettuata una richiesta di FullTrust. Da questo momento, i risultati della verifica di autorizzazione vengono memorizzati nella cache, congiuntamente al modello di sicurezza di Windows. È necessario essere certi di non esporre accidentalmente il contenuto della sequenza di record a un utente non autorizzato.

Costruttori

Proprietà

Metodi

Eventi

Si applica a