FileRecordSequence 类
定义
重要
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实现文件 IRecordSequence 顶部。 此类不能被继承。
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- 继承
-
FileRecordSequence
- 实现
示例
以下示例创建记录序列，向其追加记录，最后读取记录。
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
注解
FileRecordSequence这是基于文件系统中的单个日志文件的记录序列。 它是接口的 IRecordSequence 简单实现，位于基于文件的简单日志之上。
若要操作基于文件的日志，应用程序在其中运行的帐户必须具有足够的权限，因为构造时由文件系统安全性 FileRecordSequence 决定。 此外，在构造时对 FullTrust 的需求也是必需的。 权限验证结果会随Windows安全模型一起缓存。 应确保不会意外地将记录序列的内容公开给未经授权的用户。
构造函数
| 名称 | 说明 |
|---|---|
| FileRecordSequence(String, FileAccess, Int32) |
使用指定的文件、访问模式和文件大小初始化类的新实例 FileRecordSequence 。 |
| FileRecordSequence(String, FileAccess) |
使用指定的文件和访问模式初始化类的新实例 FileRecordSequence 。 |
| FileRecordSequence(String) |
使用指定的文件初始化类的新实例 FileRecordSequence 。 |
属性
| 名称 | 说明 |
|---|---|
| BaseSequenceNumber |
获取当前 FileRecordSequence中第一个有效记录的序列号。 |
| LastSequenceNumber |
获取大于追加的最后一条记录的序列号。 |
| MaximumRecordLength |
获取可追加到此序列或从此序列中读取的最大记录的大小（以字节为单位）。 |
| ReservedBytes |
获取已保留的字节总数。 |
| RestartSequenceNumber |
获取最近写入的重启区域的序列号。 |
| RetryAppend |
获取或设置一个值，该值指示是否在日志已满时自动重试追加。 |
方法
活动
| 名称 | 说明 |
|---|---|
| TailPinned |
当记录序列确定尾部必须向前移动时发生。 无法继承此方法。 |