FileRecordSequence 類別
定義
重要
部分資訊涉及發行前產品，在發行之前可能會有大幅修改。 Microsoft 對此處提供的資訊，不做任何明確或隱含的瑕疵擔保。
在檔案頂端實作 IRecordSequence。 此類別無法獲得繼承。
public ref class FileRecordSequence sealed : IDisposable, System::IO::Log::IRecordSequencepublic sealed class FileRecordSequence : IDisposable, System.IO.Log.IRecordSequencetype FileRecordSequence = class
interface IRecordSequence
interface IDisposablePublic NotInheritable Class FileRecordSequence
Implements IDisposable, IRecordSequence- 繼承
-
FileRecordSequence
- 實作
範例
下列範例會建立記錄順序，並附加記錄到其中，最後再讀取記錄。
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
FileRecordSequence 是根據檔案系統中單一記錄檔的記錄順序。 這是 IRecordSequence 介面的簡單實作，其建構在簡單檔案記錄之上。
若要操作簡單檔案記錄，執行應用程式所使用的帳戶必須依照檔案系統安全性在建構 FileRecordSequence 時的指定，取得足夠的權限。 另外，在建構階段中還會要求 FullTrust 權限。 在此之後，權限驗證結果會存放在快取中，以便與 Windows 安全性模型保持一致。 您務必要避免不小心將記錄順序內容公開給未經授權的使用者。
建構函式
| FileRecordSequence(String) |
使用指定的檔案，初始化 FileRecordSequence 類別的新執行個體。 |
| FileRecordSequence(String, FileAccess) |
使用指定的檔案和存取模式初始化 FileRecordSequence 類別的新執行個體。 |
| FileRecordSequence(String, FileAccess, Int32) |
使用指定的檔案、存取模式和檔案大小初始化 FileRecordSequence 類別的新執行個體。 |
屬性
| BaseSequenceNumber |
取得目前 中第一個有效記錄的序號。 |
| LastSequenceNumber |
取得大於上一筆附加記錄的序號。 |
| MaximumRecordLength |
取得可在順序中附加或讀取之最大記錄的大小 (以位元組為單位)。 |
| ReservedBytes |
取得保留的位元組總數。 |
| RestartSequenceNumber |
取得最近寫入之重新啟動區域的序號。 |
| RetryAppend |
取得或設定值，這個值表示是否在記錄已滿時自動重試附加作業。 |
方法
事件
| TailPinned |
會在記錄順序判斷必須將結尾往前移動時發生。 這個方法無法被繼承。 |
