FileRecordSequence 建構函式

public:
 FileRecordSequence(System::String ^ path);

public FileRecordSequence(string path);

new System.IO.Log.FileRecordSequence : string -> System.IO.Log.FileRecordSequence

Public Sub New (path As String)

參數

例外狀況

範例

以下範例建立一個記錄序列，將記錄附加到該序列上，讀取記錄，最後處理該序列。

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

備註

此建構子建立檔案的讀寫存取，並以共享讀取權限開啟檔案。 這表示此程序或其他程序嘗試開啟檔案以寫入時，必須先處理該 FileRecordSequence 實例，否則讀取嘗試會成功。 若 path 找不到，則會建立一個大小為 0 的新檔案。

public:
 FileRecordSequence(System::String ^ path, System::IO::FileAccess access);

public FileRecordSequence(string path, System.IO.FileAccess access);

new System.IO.Log.FileRecordSequence : string * System.IO.FileAccess -> System.IO.Log.FileRecordSequence

Public Sub New (path As String, access As FileAccess)

參數

例外狀況

public:
 FileRecordSequence(System::String ^ path, System::IO::FileAccess access, int size);

public FileRecordSequence(string path, System.IO.FileAccess access, int size);

new System.IO.Log.FileRecordSequence : string * System.IO.FileAccess * int -> System.IO.Log.FileRecordSequence

Public Sub New (path As String, access As FileAccess, size As Integer)

參數

例外狀況