LogExtentCollection LogExtentCollection LogExtentCollection LogExtentCollection Class

定义

表示与 LogExtent 关联的 LogStore 对象的集合。Represents the collection of LogExtent objects associated with a LogStore.

public ref class LogExtentCollection sealed : System::Collections::Generic::IEnumerable<System::IO::Log::LogExtent ^>
public sealed class LogExtentCollection : System.Collections.Generic.IEnumerable<System.IO.Log.LogExtent>
type LogExtentCollection = class
    interface seq<LogExtent>
    interface IEnumerable
Public NotInheritable Class LogExtentCollection
Implements IEnumerable(Of LogExtent)
继承
LogExtentCollectionLogExtentCollectionLogExtentCollectionLogExtentCollection
实现

示例

此示例演示如何使用 LogExtentLogExtentCollection 类来添加和模拟日志序列中的范围。This example shows how to use the LogExtent and LogExtentCollection classes to add and emulate extents in a log sequence.

using System;
using System.IO;
using System.Collections.Generic;
using System.Text;
using System.IO.Log;

namespace MyLogRecordSequence
{
    public class MyLog
    {
        string logName = "test.log";
        string logContainer = "MyExtent0";
        int containerSize = 32 * 1024;
        LogRecordSequence sequence = null;
        bool delete = true;

        // These are used in the TailPinned event handler.
        public static LogRecordSequence MySequence = null;
        public static bool AdvanceBase = true;

        public MyLog()
        {
            // Create a LogRecordSequence.
            sequence = new LogRecordSequence(this.logName,
                                              FileMode.CreateNew,
                                              FileAccess.ReadWrite,
                                              FileShare.None);

            // At least one container/extent must be added for Log Record Sequence.
            sequence.LogStore.Extents.Add(this.logContainer, this.containerSize);
     
            MySequence = sequence;

        }

        public void AddExtents()
        {
            // Add two additional extents. The extents are 
            // of the same size as the first extent.
            sequence.LogStore.Extents.Add("MyExtent1");
            sequence.LogStore.Extents.Add("MyExtent2");
        }

        public void EnumerateExtents()
        {
            LogStore store = sequence.LogStore;

            Console.WriteLine("Enumerating Log Extents...");
            Console.WriteLine("    Extent Count: {0} extents", store.Extents.Count);
            Console.WriteLine("    Extents Are...");
            foreach (LogExtent extent in store.Extents)
            {
                Console.WriteLine("      {0} ({1}, {2})",
                                  Path.GetFileName(extent.Path),
                                  extent.Size,
                                  extent.State);
            }
            Console.WriteLine("    Free Extents: {0} Free", store.Extents.FreeCount);   
        }

        public void SetLogPolicy()
        {
            Console.WriteLine();
            Console.WriteLine("Setting current log policy...");

            // SET LOG POLICY

            LogPolicy policy = sequence.LogStore.Policy;

            // Set AutoGrow policy. This enables the log to automatically grow
            // when the existing extents are full. New extents are added until
            // we reach the MaximumExtentCount extents.
            // AutoGrow policy is supported only in Windows Vista and not available in R2.
            
            //policy.AutoGrow = true;

            // Set the Growth Rate in terms of extents. This policy specifies
            // "how much" the log should grow. 
            policy.GrowthRate = new PolicyUnit(2, PolicyUnitType.Extents);

            // Set the AutoShrink policy. This enables the log to automatically
            // shrink if the available free space exceeds the shrink percentage. 
            // AutoGrow/shrink policy is supported only in Windows Vista and not available in R2.
            
            //policy.AutoShrinkPercentage = new PolicyUnit(30, PolicyUnitType.Percentage);

            // Set the PinnedTailThreshold policy.
            // A tail pinned event is triggered when there is no
            // log space available and log space may be freed by advancing the base.
            // The user must handle the tail pinned event by advancing the base of the log. 
            // If the user is not able to move the base of the log, the user should report with exception in
            // the tail pinned handler.
            // PinnedTailThreashold policy dictates the amount of space that the TailPinned event requests 
            // for advancing the base of the log. The amount of space can be in percentage or in terms of bytes 
            // which is rounded off to the nearest containers in CLFS. The default is 35 percent.

            
            policy.PinnedTailThreshold = new PolicyUnit(10, PolicyUnitType.Percentage);

            // Set the maximum extents the log can have.
            policy.MaximumExtentCount = 6;
            
            // Set the minimum extents the log can have.
            policy.MinimumExtentCount = 2;
            
            // Set the prefix for new containers that are added. 
            // when AutoGrow is enabled.
            //policy.NewExtentPrefix = "MyLogPrefix";
            
            // Set the suffix number for new containers that are added.
            // when AutoGrow is enabled. 
            policy.NextExtentSuffix = 3;

            // Commit the log policy.
            policy.Commit();

            // Refresh updates the IO.Log policy properties with current log policy 
            // set in the log. 
            policy.Refresh();

            // LOG POLICY END
            // 

            //+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
            // Setting up IO.Log provided capabilities...
            // 

            // SET RETRY APPEND

            // IO.Log provides a mechanism similar to AutoGrow.
            // If the existing log is full and an append fails, setting RetryAppend
            // invokes the CLFS policy engine to add new extents and re-tries
            // record appends. If MaximumExtent count has been reached, 
            // a SequenceFullException is thrown. 
            // 

            sequence.RetryAppend = true;

            // RETRY APPEND END

            // REGISTER FOR TAILPINNED EVENT NOTIFICATIONS

            // Register for TailPinned Event by passing in an event handler.
            // An event is raised when the log full condition is reached.
            // The user should either advance the base sequence number to the 
            // nearest valid sequence number recommended in the tail pinned event or
            // report a failure that it is not able to advance the base sequence 
            // number. 
            //

            sequence.TailPinned += new EventHandler<TailPinnedEventArgs>(HandleTailPinned);  

            Console.WriteLine("Done...");
        }

        public void ShowLogPolicy()
        {
            Console.WriteLine();
            Console.WriteLine("Showing current log policy...");

            LogPolicy policy = sequence.LogStore.Policy;

            Console.WriteLine("    Minimum extent count:  {0}", policy.MinimumExtentCount);
            Console.WriteLine("    Maximum extent count:  {0}", policy.MaximumExtentCount);
            Console.WriteLine("    Growth rate:           {0}", policy.GrowthRate);
            Console.WriteLine("    Pinned tail threshold: {0}", policy.PinnedTailThreshold);
            Console.WriteLine("    Auto shrink percent:   {0}", policy.AutoShrinkPercentage);
            Console.WriteLine("    Auto grow enabled:     {0}", policy.AutoGrow);
            Console.WriteLine("    New extent prefix:     {0}", policy.NewExtentPrefix);
            Console.WriteLine("    Next extent suffix:    {0}", policy.NextExtentSuffix);

	}

        // Append records. Appending three records.  
        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 LogRecordSequence..."), 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();
        }

        public void FillLog()
        {
            bool append = true;

            while (append)
            {
                try
                {
                    sequence.Append(CreateData(16 * 1024), SequenceNumber.Invalid, SequenceNumber.Invalid, RecordAppendOptions.ForceFlush);
                }

                catch (SequenceFullException)
                {
                    Console.WriteLine("Log is Full...");
                    append = false;
                }
            }
        }

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

            // Delete the log file.
            if (delete)
            {
                try
                {
                    // This deletes the base log file and all the extents associated with the log.
                    LogStore.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);
        }

        public static IList<ArraySegment<byte>> CreateData(int size)
        {
            byte[] array = new byte[size];

            Random rnd = new Random();
            rnd.NextBytes(array);

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

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

        public static SequenceNumber GetAdvanceBaseSeqNumber(SequenceNumber recTargetSeqNum)
        {
            SequenceNumber targetSequenceNumber = SequenceNumber.Invalid;

            Console.WriteLine("Getting actual target sequence number...");
            
            // 
            // Implement the logic for returning a valid sequence number closer to
            // recommended target sequence number. 
            //

            return targetSequenceNumber;
        }

        public static void HandleTailPinned(object arg, TailPinnedEventArgs tailPinnedEventArgs)
        {
            Console.WriteLine("TailPinned has fired");

            // Based on the implementation of a logging application, the log base can be moved
            // to free up more log space and if it is not possible to move the 
            // base, the application should report by throwing an exception.

            if(MyLog.AdvanceBase)
            {
                try
                {
                    // TailPnnedEventArgs has the recommended sequence number and its generated 
                    // based on PinnedTailThreshold policy. 
                    // This does not map to an actual sequence number in the record sequence
                    // but an approximation and potentially frees up the threshold % log space
                    // when the log base is advanced to a valid sequence number closer to the 
                    // recommended sequence number. 
                    // The user should use this sequence number to locate a closest valid sequence
                    // number to advance the base of the log.

                    SequenceNumber recommendedTargetSeqNum = tailPinnedEventArgs.TargetSequenceNumber; 
                    
                    // Get the actual Target sequence number.
                    SequenceNumber actualTargetSeqNum = MyLog.GetAdvanceBaseSeqNumber(recommendedTargetSeqNum);

                    MySequence.AdvanceBaseSequenceNumber(actualTargetSeqNum);
                }
                catch (Exception e)
                {
                    Console.WriteLine("Exception thrown {0} {1}", e.GetType(), e.Message);
                }
            }
            else
            {
                // Report back Error if under some conditions the log cannot
                // advance the base sequence number.

                Console.WriteLine("Reporting Error! Unable to move the base sequence number!");
                throw new IOException();
            }
        }
    }

    class LogSample
    {
        static void Main(string[] args)
        {
            // Create log record sequence.
            MyLog log = new MyLog();

            // Add additional extents.
            log.AddExtents();

            // Enumerate the current log extents.
            log.EnumerateExtents();

            // Set log policies and register for TailPinned event notifications. 
            log.SetLogPolicy();

            log.ShowLogPolicy();
            
            // Append a few records and read the appended records. 
            log.AppendRecords();
            log.ReadRecords();

            // Fill the Log to trigger log growth...and subsequent TailPinned notifications.
            log.FillLog();

            log.EnumerateExtents();

            log.Cleanup();
        }
    }
}


Imports System.IO
Imports System.Collections.Generic
Imports System.Text
Imports System.IO.Log

Namespace MyLogRecordSequence
	Public Class MyLog
		Private logName As String = "test.log"
		Private logContainer As String = "MyExtent0"
		Private containerSize As Integer = 32 * 1024
		Private sequence As LogRecordSequence = Nothing
		Private delete As Boolean = True

		' These are used in the TailPinned event handler.
		Public Shared MySequence As LogRecordSequence = Nothing
		Public Shared AdvanceBase As Boolean = True

		Public Sub New()
			' Create a LogRecordSequence.
			sequence = New LogRecordSequence(Me.logName, FileMode.CreateNew, FileAccess.ReadWrite, FileShare.None)

			' At least one container/extent must be added for Log Record Sequence.
			sequence.LogStore.Extents.Add(Me.logContainer, Me.containerSize)

			MySequence = sequence

		End Sub

		Public Sub AddExtents()
			' Add two additional extents. The extents are 
			' of the same size as the first extent.
			sequence.LogStore.Extents.Add("MyExtent1")
			sequence.LogStore.Extents.Add("MyExtent2")
		End Sub

		Public Sub EnumerateExtents()
			Dim store As LogStore = sequence.LogStore

			Console.WriteLine("Enumerating Log Extents...")
			Console.WriteLine("    Extent Count: {0} extents", store.Extents.Count)
			Console.WriteLine("    Extents Are...")
            For Each extent In store.Extents
                Console.WriteLine("      {0} ({1}, {2})", Path.GetFileName(extent.Path), extent.Size, extent.State)
            Next extent
			Console.WriteLine("    Free Extents: {0} Free", store.Extents.FreeCount)
		End Sub

		Public Sub SetLogPolicy()
			Console.WriteLine()
			Console.WriteLine("Setting current log policy...")

			' SET LOG POLICY

			Dim policy As LogPolicy = sequence.LogStore.Policy

			' Set AutoGrow policy. This enables the log to automatically grow
			' when the existing extents are full. New extents are added until
			' we reach the MaximumExtentCount extents.
			' AutoGrow policy is supported only in Windows Vista and not available in R2.

			'policy.AutoGrow = true;

			' Set the Growth Rate in terms of extents. This policy specifies
			' "how much" the log should grow. 
			policy.GrowthRate = New PolicyUnit(2, PolicyUnitType.Extents)

			' Set the AutoShrink policy. This enables the log to automatically
			' shrink if the available free space exceeds the shrink percentage. 
			' AutoGrow/shrink policy is supported only in Windows Vista and not available in R2.

			'policy.AutoShrinkPercentage = new PolicyUnit(30, PolicyUnitType.Percentage);

			' Set the PinnedTailThreshold policy.
			' A tail pinned event is triggered when there is no
			' log space available and log space may be freed by advancing the base.
			' The user must handle the tail pinned event by advancing the base of the log. 
			' If the user is not able to move the base of the log, the user should report with exception in
			' the tail pinned handler.
			' PinnedTailThreashold policy dictates the amount of space that the TailPinned event requests 
			' for advancing the base of the log. The amount of space can be in percentage or in terms of bytes 
			' which is rounded off to the nearest containers in CLFS. The default is 35 percent.


			policy.PinnedTailThreshold = New PolicyUnit(10, PolicyUnitType.Percentage)

			' Set the maximum extents the log can have.
			policy.MaximumExtentCount = 6

			' Set the minimum extents the log can have.
			policy.MinimumExtentCount = 2

			' Set the prefix for new containers that are added. 
			' when AutoGrow is enabled.
			'policy.NewExtentPrefix = "MyLogPrefix";

			' Set the suffix number for new containers that are added.
			' when AutoGrow is enabled. 
			policy.NextExtentSuffix = 3

			' Commit the log policy.
			policy.Commit()

			' Refresh updates the IO.Log policy properties with current log policy 
			' set in the log. 
			policy.Refresh()

			' LOG POLICY END
			' 

			'+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
			' Setting up IO.Log provided capabilities...
			' 

			' SET RETRY APPEND

			' IO.Log provides a mechanism similar to AutoGrow.
			' If the existing log is full and an append fails, setting RetryAppend
			' invokes the CLFS policy engine to add new extents and re-tries
			' record appends. If MaximumExtent count has been reached, 
			' a SequenceFullException is thrown. 
			' 

			sequence.RetryAppend = True

			' RETRY APPEND END

			' REGISTER FOR TAILPINNED EVENT NOTIFICATIONS

			' Register for TailPinned Event by passing in an event handler.
			' An event is raised when the log full condition is reached.
			' The user should either advance the base sequence number to the 
			' nearest valid sequence number recommended in the tail pinned event or
			' report a failure that it is not able to advance the base sequence 
			' number. 
			'

			AddHandler sequence.TailPinned, AddressOf HandleTailPinned

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

		Public Sub ShowLogPolicy()
			Console.WriteLine()
			Console.WriteLine("Showing current log policy...")

			Dim policy As LogPolicy = sequence.LogStore.Policy

			Console.WriteLine("    Minimum extent count:  {0}", policy.MinimumExtentCount)
			Console.WriteLine("    Maximum extent count:  {0}", policy.MaximumExtentCount)
			Console.WriteLine("    Growth rate:           {0}", policy.GrowthRate)
			Console.WriteLine("    Pinned tail threshold: {0}", policy.PinnedTailThreshold)
			Console.WriteLine("    Auto shrink percent:   {0}", policy.AutoShrinkPercentage)
			Console.WriteLine("    Auto grow enabled:     {0}", policy.AutoGrow)
			Console.WriteLine("    New extent prefix:     {0}", policy.NewExtentPrefix)
			Console.WriteLine("    Next extent suffix:    {0}", policy.NextExtentSuffix)

		End Sub

		' Append records. Appending three records.  
		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 LogRecordSequence..."), 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 As LogRecord 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

		Public Sub FillLog()
			Dim append As Boolean = True

			Do While append
				Try
					sequence.Append(CreateData(16 * 1024), SequenceNumber.Invalid, SequenceNumber.Invalid, RecordAppendOptions.ForceFlush)

				Catch e1 As SequenceFullException
					Console.WriteLine("Log is Full...")
					append = False
				End Try
			Loop
		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
					' This deletes the base log file and all the extents associated with the log.
					LogStore.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

		Public Shared Function CreateData(ByVal size As Integer) As IList(Of ArraySegment(Of Byte))
			Dim array(size - 1) As Byte

			Dim rand As New Random()
			rand.NextBytes(array)

			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

		Public Shared Function GetAdvanceBaseSeqNumber(ByVal recTargetSeqNum As SequenceNumber) As SequenceNumber
			Dim targetSequenceNumber As SequenceNumber = SequenceNumber.Invalid

			Console.WriteLine("Getting actual target sequence number...")

			' 
			' Implement the logic for returning a valid sequence number closer to
			' recommended target sequence number. 
			'

			Return targetSequenceNumber
		End Function

		Public Shared Sub HandleTailPinned(ByVal arg As Object, ByVal tailPinnedEventArgs As TailPinnedEventArgs)
			Console.WriteLine("TailPinned has fired")

			' Based on the implementation of a logging application, the log base can be moved
			' to free up more log space and if it is not possible to move the 
			' base, the application should report by throwing an exception.

			If MyLog.AdvanceBase Then
				Try
					' TailPnnedEventArgs has the recommended sequence number and its generated 
					' based on PinnedTailThreshold policy. 
					' This does not map to an actual sequence number in the record sequence
					' but an approximation and potentially frees up the threshold % log space
					' when the log base is advanced to a valid sequence number closer to the 
					' recommended sequence number. 
					' The user should use this sequence number to locate a closest valid sequence
					' number to advance the base of the log.

					Dim recommendedTargetSeqNum As SequenceNumber = tailPinnedEventArgs.TargetSequenceNumber

					' Get the actual Target sequence number.
					Dim actualTargetSeqNum As SequenceNumber = MyLog.GetAdvanceBaseSeqNumber(recommendedTargetSeqNum)

					MySequence.AdvanceBaseSequenceNumber(actualTargetSeqNum)
				Catch e As Exception
					Console.WriteLine("Exception thrown {0} {1}", e.GetType(), e.Message)
				End Try
			Else
				' Report back Error if under some conditions the log cannot
				' advance the base sequence number.

				Console.WriteLine("Reporting Error! Unable to move the base sequence number!")
				Throw New IOException()
			End If
		End Sub
	End Class

	Friend Class LogSample
		Shared Sub Main(ByVal args() As String)
			' Create log record sequence.
			Dim log As New MyLog()

			' Add additional extents.
			log.AddExtents()

			' Enumerate the current log extents.
			log.EnumerateExtents()

			' Set log policies and register for TailPinned event notifications. 
			log.SetLogPolicy()

			log.ShowLogPolicy()

			' Append a few records and read the appended records. 
			log.AppendRecords()
			log.ReadRecords()

			' Fill the Log to trigger log growth...and subsequent TailPinned notifications.
			log.FillLog()

			log.EnumerateExtents()

			log.Cleanup()
		End Sub
	End Class
End Namespace

注解

此类包含与 LogExtent 关联的 LogStore 对象的集合。This class contains a collection of LogExtent objects associated with a LogStore. LogStore 实例将其数据存储在磁盘范围的集合中,这些范围由 LogExtent 实例表示。A LogStore instance stores its data in a collection of disk extents, represented by LogExtent instances. 特定的 LogExtent 与一个 LogStore 相关联,同一 LogExtent 中的 LogStore 对象具有相同的大小。A particular LogExtent is associated with one LogStore, and LogExtent objects in the same LogStore are of identical size. 将以范围增量的形式在 LogStore 实例中添加和移除空间。Space is added to and removed from a LogStore instance in extent increments.

虽然 LogExtent 对象在磁盘上以文件的形式表示,但不应像普通文件那样移动或删除它们。Although LogExtent objects are represented on disk as files, they should not be moved or deleted as normal files. 相反,应使用此类提供的方法直接添加和删除 LogExtent 实例。Rather, you should use the methods provided by this class for adding and deleting LogExtent instances directly. 当范围不再包含任何活动数据时,通常会将其移除。Extents are usually removed when they no longer contain any active data. 但是,如果 force 方法中的 Remove 参数为 true,并且无法立即移除范围,则会引发异常。However, if the force parameter in the Remove method is true, an exception is thrown if they cannot be removed immediately.

无法移除 LogExtentCollection 中的最后一个范围,这意味着在添加范围后 Count 属性不能为零。You cannot remove the last extent in the LogExtentCollection, which means that the Count property cannot be zero after an extent is added.

属性

Count Count Count Count

获取集合中的日志范围数。Gets the number of log extents in the collection.

FreeCount FreeCount FreeCount FreeCount

获取集合中的可用 LogExtent 实例数,即,不包含任何数据的 LogExtent 实例数。Gets the number of free LogExtent instances in the collection, that is, the number of LogExtent instances that do not contain any data.

方法

Add(String) Add(String) Add(String) Add(String)

将一个 LogExtent 实例添加到集合中。Adds a LogExtent instance to the collection.

Add(String, Int64) Add(String, Int64) Add(String, Int64) Add(String, Int64)

使用指定大小创建新的 LogExtent,并将其添加到集合中。Creates a new LogExtent with the specified size and adds it to the collection.

Equals(Object) Equals(Object) Equals(Object) Equals(Object)

确定指定的对象是否等于当前对象。Determines whether the specified object is equal to the current object.

(Inherited from Object)
GetEnumerator() GetEnumerator() GetEnumerator() GetEnumerator()

获取此集合中 LogExtent 实例的枚举数。Gets an enumerator for the LogExtent instances in this collection. 不能继承此方法。This method cannot be inherited.

GetHashCode() GetHashCode() GetHashCode() GetHashCode()

作为默认哈希函数。Serves as the default hash function.

(Inherited from Object)
GetType() GetType() GetType() GetType()

获取当前实例的 TypeGets the Type of the current instance.

(Inherited from Object)
MemberwiseClone() MemberwiseClone() MemberwiseClone() MemberwiseClone()

创建当前 Object 的浅表副本。Creates a shallow copy of the current Object.

(Inherited from Object)
Remove(LogExtent, Boolean) Remove(LogExtent, Boolean) Remove(LogExtent, Boolean) Remove(LogExtent, Boolean)

从集合中移除指定的 LogExtent 实例。Removes the specified LogExtent instance from the collection.

Remove(String, Boolean) Remove(String, Boolean) Remove(String, Boolean) Remove(String, Boolean)

从集合中移除具有指定路径的 LogExtent 实例。Removes the LogExtent instance with the specified path from the collection.

ToString() ToString() ToString() ToString()

返回表示当前对象的字符串。Returns a string that represents the current object.

(Inherited from Object)

显式界面实现

IEnumerable.GetEnumerator() IEnumerable.GetEnumerator() IEnumerable.GetEnumerator() IEnumerable.GetEnumerator()

获取此集合中 LogExtent 实例的枚举数。Gets an enumerator for the LogExtent instances in this collection. 不能继承此方法。This method cannot be inherited.

扩展方法

CopyToDataTable<T>(IEnumerable<T>) CopyToDataTable<T>(IEnumerable<T>) CopyToDataTable<T>(IEnumerable<T>) CopyToDataTable<T>(IEnumerable<T>)

在给定其泛型参数 TDataTable 的输入 DataRow 对象的情况下,返回包含 IEnumerable<T> 对象副本的 DataRowReturns a DataTable that contains copies of the DataRow objects, given an input IEnumerable<T> object where the generic parameter T is DataRow.

CopyToDataTable<T>(IEnumerable<T>, DataTable, LoadOption) CopyToDataTable<T>(IEnumerable<T>, DataTable, LoadOption) CopyToDataTable<T>(IEnumerable<T>, DataTable, LoadOption) CopyToDataTable<T>(IEnumerable<T>, DataTable, LoadOption)

在给定其泛型参数 TDataRow 的输入 DataTable 对象的情况下,将 IEnumerable<T> 对象复制到指定的 DataRowCopies DataRow objects to the specified DataTable, given an input IEnumerable<T> object where the generic parameter T is DataRow.

CopyToDataTable<T>(IEnumerable<T>, DataTable, LoadOption, FillErrorEventHandler) CopyToDataTable<T>(IEnumerable<T>, DataTable, LoadOption, FillErrorEventHandler) CopyToDataTable<T>(IEnumerable<T>, DataTable, LoadOption, FillErrorEventHandler) CopyToDataTable<T>(IEnumerable<T>, DataTable, LoadOption, FillErrorEventHandler)

在给定其泛型参数 TDataRow 的输入 DataTable 对象的情况下,将 IEnumerable<T> 对象复制到指定的 DataRowCopies DataRow objects to the specified DataTable, given an input IEnumerable<T> object where the generic parameter T is DataRow.

Cast<TResult>(IEnumerable) Cast<TResult>(IEnumerable) Cast<TResult>(IEnumerable) Cast<TResult>(IEnumerable)

IEnumerable 的元素强制转换为指定的类型。Casts the elements of an IEnumerable to the specified type.

OfType<TResult>(IEnumerable) OfType<TResult>(IEnumerable) OfType<TResult>(IEnumerable) OfType<TResult>(IEnumerable)

根据指定类型筛选 IEnumerable 的元素。Filters the elements of an IEnumerable based on a specified type.

AsParallel(IEnumerable) AsParallel(IEnumerable) AsParallel(IEnumerable) AsParallel(IEnumerable)

启用查询的并行化。Enables parallelization of a query.

AsQueryable(IEnumerable) AsQueryable(IEnumerable) AsQueryable(IEnumerable) AsQueryable(IEnumerable)

IEnumerable 转换为 IQueryableConverts an IEnumerable to an IQueryable.

Ancestors<T>(IEnumerable<T>) Ancestors<T>(IEnumerable<T>) Ancestors<T>(IEnumerable<T>) Ancestors<T>(IEnumerable<T>)

返回元素集合,其中包含源集合中每个节点的上级。Returns a collection of elements that contains the ancestors of every node in the source collection.

Ancestors<T>(IEnumerable<T>, XName) Ancestors<T>(IEnumerable<T>, XName) Ancestors<T>(IEnumerable<T>, XName) Ancestors<T>(IEnumerable<T>, XName)

返回经过筛选的元素集合,其中包含源集合中每个节点的上级。Returns a filtered collection of elements that contains the ancestors of every node in the source collection. 集合中仅包括具有匹配 XName 的元素。Only elements that have a matching XName are included in the collection.

DescendantNodes<T>(IEnumerable<T>) DescendantNodes<T>(IEnumerable<T>) DescendantNodes<T>(IEnumerable<T>) DescendantNodes<T>(IEnumerable<T>)

返回源集合中每个文档和元素的子代节点的集合。Returns a collection of the descendant nodes of every document and element in the source collection.

Descendants<T>(IEnumerable<T>) Descendants<T>(IEnumerable<T>) Descendants<T>(IEnumerable<T>) Descendants<T>(IEnumerable<T>)

返回元素集合,其中包含源集合中每个元素和文档的子代元素。Returns a collection of elements that contains the descendant elements of every element and document in the source collection.

Descendants<T>(IEnumerable<T>, XName) Descendants<T>(IEnumerable<T>, XName) Descendants<T>(IEnumerable<T>, XName) Descendants<T>(IEnumerable<T>, XName)

返回经过筛选的元素集合,其中包含源集合中每个元素和文档的子代元素。Returns a filtered collection of elements that contains the descendant elements of every element and document in the source collection. 集合中仅包括具有匹配 XName 的元素。Only elements that have a matching XName are included in the collection.

Elements<T>(IEnumerable<T>) Elements<T>(IEnumerable<T>) Elements<T>(IEnumerable<T>) Elements<T>(IEnumerable<T>)

返回源集合中每个元素和文档的子元素的集合。Returns a collection of the child elements of every element and document in the source collection.

Elements<T>(IEnumerable<T>, XName) Elements<T>(IEnumerable<T>, XName) Elements<T>(IEnumerable<T>, XName) Elements<T>(IEnumerable<T>, XName)

返回源集合中经过筛选的每个元素和文档的子元素集合。Returns a filtered collection of the child elements of every element and document in the source collection. 集合中仅包括具有匹配 XName 的元素。Only elements that have a matching XName are included in the collection.

InDocumentOrder<T>(IEnumerable<T>) InDocumentOrder<T>(IEnumerable<T>) InDocumentOrder<T>(IEnumerable<T>) InDocumentOrder<T>(IEnumerable<T>)

返回节点集合(其中包含源集合中的所有节点),并按文档顺序排列。Returns a collection of nodes that contains all nodes in the source collection, sorted in document order.

Nodes<T>(IEnumerable<T>) Nodes<T>(IEnumerable<T>) Nodes<T>(IEnumerable<T>) Nodes<T>(IEnumerable<T>)

返回源集合中每个文档和元素的子节点集合。Returns a collection of the child nodes of every document and element in the source collection.

Remove<T>(IEnumerable<T>) Remove<T>(IEnumerable<T>) Remove<T>(IEnumerable<T>) Remove<T>(IEnumerable<T>)

将源集合中的每个节点从其父节点中移除。Removes every node in the source collection from its parent node.

适用于

另请参阅