ReaderWriterLock Kelas

Definisi

Ruang nama:

System.Threading

Rakitan:

System.Threading.dll

Sumber:

ReaderWriterLock.cs

Menentukan kunci yang mendukung penulis tunggal dan beberapa pembaca.

public ref class ReaderWriterLock sealed : System::Runtime::ConstrainedExecution::CriticalFinalizerObject

public sealed class ReaderWriterLock : System.Runtime.ConstrainedExecution.CriticalFinalizerObject

type ReaderWriterLock = class
    inherit CriticalFinalizerObject

Public NotInheritable Class ReaderWriterLock
Inherits CriticalFinalizerObject

Warisan

Object

CriticalFinalizerObject

ReaderWriterLock

Contoh

Contoh berikut menunjukkan cara menggunakan ReaderWriterLock untuk melindungi sumber daya bersama, nilai bilangan bulat bernama resource, yang dibaca secara bersamaan dan ditulis secara eksklusif oleh beberapa utas. Perhatikan bahwa ReaderWriterLock dideklarasikan pada tingkat kelas sehingga terlihat oleh semua utas.

// This example shows a ReaderWriterLock protecting a shared
// resource that is read concurrently and written exclusively
// by multiple threads.
// The complete code is located in the ReaderWriterLock
// class topic.
using namespace System;
using namespace System::Threading;
public ref class Test
{
public:

   // Declaring the ReaderWriterLock at the class level
   // makes it visible to all threads.
   static ReaderWriterLock^ rwl = gcnew ReaderWriterLock;

   // For this example, the shared resource protected by the
   // ReaderWriterLock is just an integer.
   static int resource = 0;

   literal int numThreads = 26;
   static bool running = true;

   // Statistics.
   static int readerTimeouts = 0;
   static int writerTimeouts = 0;
   static int reads = 0;
   static int writes = 0;
   static void ThreadProc()
   {
      Random^ rnd = gcnew Random;

      // As long as a thread runs, it randomly selects
      // various ways to read and write from the shared
      // resource. Each of the methods demonstrates one
      // or more features of ReaderWriterLock.
      while ( running )
      {
         double action = rnd->NextDouble();
         if ( action < .8 )
                  ReadFromResource( 10 );
         else
         if ( action < .81 )
                  ReleaseRestore( rnd, 50 );
         else
         if ( action < .90 )
                  UpgradeDowngrade( rnd, 100 );
         else
                  WriteToResource( rnd, 100 );
      }
   }


   // Shows how to request and release a reader lock, and
   // how to handle time-outs.
   static void ReadFromResource( int timeOut )
   {
      try
      {
         rwl->AcquireReaderLock( timeOut );
         try
         {

            // It is safe for this thread to read from
            // the shared resource.
            Display( String::Format( "reads resource value {0}", resource ) );
            Interlocked::Increment( reads );
         }
         finally
         {

            // Ensure that the lock is released.
            rwl->ReleaseReaderLock();
         }

      }
      catch ( ApplicationException^ )
      {

         // The reader lock request timed out.
         Interlocked::Increment( readerTimeouts );
      }

   }


   // Shows how to request and release the writer lock, and
   // how to handle time-outs.
   static void WriteToResource( Random^ rnd, int timeOut )
   {
      try
      {
         rwl->AcquireWriterLock( timeOut );
         try
         {

            // It is safe for this thread to read or write
            // from the shared resource.
            resource = rnd->Next( 500 );
            Display( String::Format( "writes resource value {0}", resource ) );
            Interlocked::Increment( writes );
         }
         finally
         {

            // Ensure that the lock is released.
            rwl->ReleaseWriterLock();
         }

      }
      catch ( ApplicationException^ )
      {

         // The writer lock request timed out.
         Interlocked::Increment( writerTimeouts );
      }

   }


   // Shows how to request a reader lock, upgrade the
   // reader lock to the writer lock, and downgrade to a
   // reader lock again.
   static void UpgradeDowngrade( Random^ rnd, int timeOut )
   {
      try
      {
         rwl->AcquireReaderLock( timeOut );
         try
         {

            // It is safe for this thread to read from
            // the shared resource.
            Display( String::Format( "reads resource value {0}", resource ) );
            Interlocked::Increment( reads );

            // If it is necessary to write to the resource,
            // you must either release the reader lock and
            // then request the writer lock, or upgrade the
            // reader lock. Note that upgrading the reader lock
            // puts the thread in the write queue, behind any
            // other threads that might be waiting for the
            // writer lock.
            try
            {
               LockCookie lc = rwl->UpgradeToWriterLock( timeOut );
               try
               {

                  // It is safe for this thread to read or write
                  // from the shared resource.
                  resource = rnd->Next( 500 );
                  Display( String::Format( "writes resource value {0}", resource ) );
                  Interlocked::Increment( writes );
               }
               finally
               {

                  // Ensure that the lock is released.
                  rwl->DowngradeFromWriterLock( lc );
               }

            }
            catch ( ApplicationException^ )
            {

               // The upgrade request timed out.
               Interlocked::Increment( writerTimeouts );
            }


            // When the lock has been downgraded, it is
            // still safe to read from the resource.
            Display( String::Format( "reads resource value {0}", resource ) );
            Interlocked::Increment( reads );
         }
         finally
         {

            // Ensure that the lock is released.
            rwl->ReleaseReaderLock();
         }

      }
      catch ( ApplicationException^ )
      {

         // The reader lock request timed out.
         Interlocked::Increment( readerTimeouts );
      }

   }


   // Shows how to release all locks and later restore
   // the lock state. Shows how to use sequence numbers
   // to determine whether another thread has obtained
   // a writer lock since this thread last accessed the
   // resource.
   static void ReleaseRestore( Random^ rnd, int timeOut )
   {
      int lastWriter;
      try
      {
         rwl->AcquireReaderLock( timeOut );
         try
         {

            // It is safe for this thread to read from
            // the shared resource. Cache the value. (You
            // might do this if reading the resource is
            // an expensive operation.)
            int resourceValue = resource;
            Display( String::Format( "reads resource value {0}", resourceValue ) );
            Interlocked::Increment( reads );

            // Save the current writer sequence number.
            lastWriter = rwl->WriterSeqNum;

            // Release the lock, and save a cookie so the
            // lock can be restored later.
            LockCookie lc = rwl->ReleaseLock();

            // Wait for a random interval (up to a
            // quarter of a second), and then restore
            // the previous state of the lock. Note that
            // there is no timeout on the Restore method.
            Thread::Sleep( rnd->Next( 250 ) );
            rwl->RestoreLock( lc );

            // Check whether other threads obtained the
            // writer lock in the interval. If not, then
            // the cached value of the resource is still
            // valid.
            if ( rwl->AnyWritersSince( lastWriter ) )
            {
               resourceValue = resource;
               Interlocked::Increment( reads );
               Display( String::Format( "resource has changed {0}", resourceValue ) );
            }
            else
            {
               Display( String::Format( "resource has not changed {0}", resourceValue ) );
            }
         }
         finally
         {

            // Ensure that the lock is released.
            rwl->ReleaseReaderLock();
         }

      }
      catch ( ApplicationException^ )
      {

         // The reader lock request timed out.
         Interlocked::Increment( readerTimeouts );
      }

   }


   // Helper method briefly displays the most recent
   // thread action. Comment out calls to Display to
   // get a better idea of throughput.
   static void Display( String^ msg )
   {
      Console::Write( "Thread {0} {1}.       \r", Thread::CurrentThread->Name, msg );
   }

};


int main()
{
   array<String^>^args = Environment::GetCommandLineArgs();

   // Start a series of threads. Each thread randomly
   // performs reads and writes on the shared resource.
   array<Thread^>^t = gcnew array<Thread^>(Test::numThreads);
   for ( int i = 0; i < Test::numThreads; i++ )
   {
      t[ i ] = gcnew Thread( gcnew ThreadStart( Test::ThreadProc ) );
      t[ i ]->Name = gcnew String( Convert::ToChar( i + 65 ),1 );
      t[ i ]->Start();
      if ( i > 10 )
            Thread::Sleep( 300 );

   }

   // Tell the threads to shut down, then wait until they all
   // finish.
   Test::running = false;
   for ( int i = 0; i < Test::numThreads; i++ )
   {
      t[ i ]->Join();

   }

   // Display statistics.
   Console::WriteLine( "\r\n {0} reads, {1} writes, {2} reader time-outs, {3} writer time-outs.", Test::reads, Test::writes, Test::readerTimeouts, Test::writerTimeouts );
   Console::WriteLine( "Press ENTER to exit." );
   Console::ReadLine();
   return 0;
}

// The complete code is located in the ReaderWriterLock class topic.
using System;
using System.Threading;

public class Example
{
   static ReaderWriterLock rwl = new ReaderWriterLock();
   // Define the shared resource protected by the ReaderWriterLock.
   static int resource = 0;

   const int numThreads = 26;
   static bool running = true;

   // Statistics.
   static int readerTimeouts = 0;
   static int writerTimeouts = 0;
   static int reads = 0;
   static int writes = 0;

   public static void Main()
   {
      // Start a series of threads to randomly read from and
      // write to the shared resource.
      Thread[] t = new Thread[numThreads];
      for (int i = 0; i < numThreads; i++){
         t[i] = new Thread(new ThreadStart(ThreadProc));
         t[i].Name = new String((char)(i + 65), 1);
         t[i].Start();
         if (i > 10)
            Thread.Sleep(300);
      }

      // Tell the threads to shut down and wait until they all finish.
      running = false;
      for (int i = 0; i < numThreads; i++)
         t[i].Join();

      // Display statistics.
      Console.WriteLine("\n{0} reads, {1} writes, {2} reader time-outs, {3} writer time-outs.",
            reads, writes, readerTimeouts, writerTimeouts);
      Console.Write("Press ENTER to exit... ");
      Console.ReadLine();
   }

   static void ThreadProc()
   {
      Random rnd = new Random();

      // Randomly select a way for the thread to read and write from the shared
      // resource.
      while (running) {
         double action = rnd.NextDouble();
         if (action < .8)
            ReadFromResource(10);
         else if (action < .81)
            ReleaseRestore(rnd, 50);
         else if (action < .90)
            UpgradeDowngrade(rnd, 100);
         else
            WriteToResource(rnd, 100);
      }
   }

   // Request and release a reader lock, and handle time-outs.
   static void ReadFromResource(int timeOut)
   {
      try {
         rwl.AcquireReaderLock(timeOut);
         try {
            // It is safe for this thread to read from the shared resource.
            Display("reads resource value " + resource);
            Interlocked.Increment(ref reads);
         }
         finally {
            // Ensure that the lock is released.
            rwl.ReleaseReaderLock();
         }
      }
      catch (ApplicationException) {
         // The reader lock request timed out.
         Interlocked.Increment(ref readerTimeouts);
      }
   }

   // Request and release the writer lock, and handle time-outs.
   static void WriteToResource(Random rnd, int timeOut)
   {
      try {
         rwl.AcquireWriterLock(timeOut);
         try {
            // It's safe for this thread to access from the shared resource.
            resource = rnd.Next(500);
            Display("writes resource value " + resource);
            Interlocked.Increment(ref writes);
         }
         finally {
            // Ensure that the lock is released.
            rwl.ReleaseWriterLock();
         }
      }
      catch (ApplicationException) {
         // The writer lock request timed out.
         Interlocked.Increment(ref writerTimeouts);
      }
   }

   // Requests a reader lock, upgrades the reader lock to the writer
   // lock, and downgrades it to a reader lock again.
   static void UpgradeDowngrade(Random rnd, int timeOut)
   {
      try {
         rwl.AcquireReaderLock(timeOut);
         try {
            // It's safe for this thread to read from the shared resource.
            Display("reads resource value " + resource);
            Interlocked.Increment(ref reads);

            // To write to the resource, either release the reader lock and
            // request the writer lock, or upgrade the reader lock. Upgrading
            // the reader lock puts the thread in the write queue, behind any
            // other threads that might be waiting for the writer lock.
            try {
               LockCookie lc = rwl.UpgradeToWriterLock(timeOut);
               try {
                  // It's safe for this thread to read or write from the shared resource.
                  resource = rnd.Next(500);
                  Display("writes resource value " + resource);
                  Interlocked.Increment(ref writes);
               }
               finally {
                  // Ensure that the lock is released.
                  rwl.DowngradeFromWriterLock(ref lc);
               }
            }
            catch (ApplicationException) {
               // The upgrade request timed out.
               Interlocked.Increment(ref writerTimeouts);
            }

            // If the lock was downgraded, it's still safe to read from the resource.
            Display("reads resource value " + resource);
            Interlocked.Increment(ref reads);
         }
         finally {
            // Ensure that the lock is released.
            rwl.ReleaseReaderLock();
         }
      }
      catch (ApplicationException) {
         // The reader lock request timed out.
         Interlocked.Increment(ref readerTimeouts);
      }
   }

   // Release all locks and later restores the lock state.
   // Uses sequence numbers to determine whether another thread has
   // obtained a writer lock since this thread last accessed the resource.
   static void ReleaseRestore(Random rnd, int timeOut)
   {
      int lastWriter;

      try {
         rwl.AcquireReaderLock(timeOut);
         try {
            // It's safe for this thread to read from the shared resource,
            // so read and cache the resource value.
            int resourceValue = resource;     // Cache the resource value.
            Display("reads resource value " + resourceValue);
            Interlocked.Increment(ref reads);

            // Save the current writer sequence number.
            lastWriter = rwl.WriterSeqNum;

            // Release the lock and save a cookie so the lock can be restored later.
            LockCookie lc = rwl.ReleaseLock();

            // Wait for a random interval and then restore the previous state of the lock.
            Thread.Sleep(rnd.Next(250));
            rwl.RestoreLock(ref lc);

            // Check whether other threads obtained the writer lock in the interval.
            // If not, then the cached value of the resource is still valid.
            if (rwl.AnyWritersSince(lastWriter)) {
               resourceValue = resource;
               Interlocked.Increment(ref reads);
               Display("resource has changed " + resourceValue);
            }
            else {
               Display("resource has not changed " + resourceValue);
            }
         }
         finally {
            // Ensure that the lock is released.
            rwl.ReleaseReaderLock();
         }
      }
      catch (ApplicationException) {
         // The reader lock request timed out.
         Interlocked.Increment(ref readerTimeouts);
      }
   }

   // Helper method briefly displays the most recent thread action.
   static void Display(string msg)
   {
      Console.Write("Thread {0} {1}.       \r", Thread.CurrentThread.Name, msg);
   }
}

' The complete code is located in the ReaderWriterLock class topic.
Imports System.Threading

Public Module Example
   Private rwl As New ReaderWriterLock()
   ' Define the shared resource protected by the ReaderWriterLock.
   Private resource As Integer = 0

   Const numThreads As Integer = 26
   Private running As Boolean = True
   
   ' Statistics.
   Private readerTimeouts As Integer = 0
   Private writerTimeouts As Integer = 0
   Private reads As Integer = 0
   Private writes As Integer = 0
  
   Public Sub Main()
      ' Start a series of threads to randomly read from and
      ' write to the shared resource.
      Dim t(numThreads - 1) As Thread
      Dim i As Integer
      For i = 0 To numThreads - 1
         t(i) = New Thread(New ThreadStart(AddressOf ThreadProc))
         t(i).Name = Chr(i + 65)
         t(i).Start()
         If i > 10 Then
            Thread.Sleep(300)
         End If
      Next

      ' Tell the threads to shut down and wait until they all finish.
      running = False
      For i = 0 To numThreads - 1
         t(i).Join()
      Next
      
      ' Display statistics.
      Console.WriteLine(vbCrLf & "{0} reads, {1} writes, {2} reader time-outs, {3} writer time-outs.",
                        reads, writes, readerTimeouts, writerTimeouts)
      Console.Write("Press ENTER to exit... ")
      Console.ReadLine()
   End Sub

   Sub ThreadProc()
      Dim rnd As New Random

      ' Randomly select a way for the thread to read and write from the shared
      ' resource.
      While running
         Dim action As Double = rnd.NextDouble()
         If action < 0.8 Then
            ReadFromResource(10)
         ElseIf action < 0.81 Then
            ReleaseRestore(rnd, 50)
         ElseIf action < 0.9 Then
            UpgradeDowngrade(rnd, 100)
         Else
            WriteToResource(rnd, 100)
         End If
      End While
   End Sub
    
   ' Request and release a reader lock, and handle time-outs.
   Sub ReadFromResource(timeOut As Integer)
      Try
         rwl.AcquireReaderLock(timeOut)
         Try
            ' It's safe for this thread to read from the shared resource.
            Display("reads resource value " & resource)
            Interlocked.Increment(reads)
         Finally
            ' Ensure that the lock is released.
            rwl.ReleaseReaderLock()
         End Try
      Catch ex As ApplicationException
         ' The reader lock request timed out.
         Interlocked.Increment(readerTimeouts)
      End Try
   End Sub

   ' Request and release the writer lock, and handle time-outs.
   Sub WriteToResource(rnd As Random, timeOut As Integer)
      Try
         rwl.AcquireWriterLock(timeOut)
         Try
            ' It's safe for this thread to read or write from the shared resource.
            resource = rnd.Next(500)
            Display("writes resource value " & resource)
            Interlocked.Increment(writes)
         Finally
            ' Ensure that the lock is released.
            rwl.ReleaseWriterLock()
         End Try
      Catch ex As ApplicationException
         ' The writer lock request timed out.
         Interlocked.Increment(writerTimeouts)
      End Try
   End Sub

   ' Requests a reader lock, upgrades the reader lock to the writer
   ' lock, and downgrades it to a reader lock again.
   Sub UpgradeDowngrade(rnd As Random, timeOut As Integer)
      Try
         rwl.AcquireReaderLock(timeOut)
         Try
            ' It's safe for this thread to read from the shared resource.
            Display("reads resource value " & resource)
            Interlocked.Increment(reads)
            
            ' To write to the resource, either release the reader lock and
            ' request the writer lock, or upgrade the reader lock. Upgrading
            ' the reader lock puts the thread in the write queue, behind any
            ' other threads that might be waiting for the writer lock.
            Try
               Dim lc As LockCookie = rwl.UpgradeToWriterLock(timeOut)
               Try
                  ' It's safe for this thread to read or write from the shared resource.
                  resource = rnd.Next(500)
                  Display("writes resource value " & resource)
                  Interlocked.Increment(writes)
               Finally
                  ' Ensure that the lock is released.
                  rwl.DowngradeFromWriterLock(lc)
               End Try
            Catch ex As ApplicationException
               ' The upgrade request timed out.
               Interlocked.Increment(writerTimeouts)
            End Try
            
            ' If the lock was downgraded, it's still safe to read from the resource.
            Display("reads resource value " & resource)
            Interlocked.Increment(reads)
         Finally
            ' Ensure that the lock is released.
            rwl.ReleaseReaderLock()
         End Try
      Catch ex As ApplicationException
         ' The reader lock request timed out.
         Interlocked.Increment(readerTimeouts)
      End Try
   End Sub

   ' Release all locks and later restores the lock state.
   ' Uses sequence numbers to determine whether another thread has
   ' obtained a writer lock since this thread last accessed the resource.
   Sub ReleaseRestore(rnd As Random ,timeOut As Integer)
      Dim lastWriter As Integer
      
      Try
         rwl.AcquireReaderLock(timeOut)
         Try
            ' It's safe for this thread to read from the shared resource,
            ' so read and cache the resource value.
            Dim resourceValue As Integer = resource
            Display("reads resource value " & resourceValue)
            Interlocked.Increment(reads)
            
            ' Save the current writer sequence number.
            lastWriter = rwl.WriterSeqNum
            
            ' Release the lock and save a cookie so the lock can be restored later.
            Dim lc As LockCookie = rwl.ReleaseLock()
            
            ' Wait for a random interval and then restore the previous state of the lock.
            Thread.Sleep(rnd.Next(250))
            rwl.RestoreLock(lc)
           
            ' Check whether other threads obtained the writer lock in the interval.
            ' If not, then the cached value of the resource is still valid.
            If rwl.AnyWritersSince(lastWriter) Then
               resourceValue = resource
               Interlocked.Increment(reads)
               Display("resource has changed " & resourceValue)
            Else
               Display("resource has not changed " & resourceValue)
            End If
         Finally
            ' Ensure that the lock is released.
            rwl.ReleaseReaderLock()
         End Try
      Catch ex As ApplicationException
         ' The reader lock request timed out.
         Interlocked.Increment(readerTimeouts)
      End Try
   End Sub

   ' Helper method briefly displays the most recent thread action.
   Sub Display(msg As String)
      Console.Write("Thread {0} {1}.       " & vbCr, Thread.CurrentThread.Name, msg)
   End Sub
End Module

Keterangan

Penting

.NET Framework memiliki dua kunci pembaca-penulis, ReaderWriterLockSlim dan ReaderWriterLock. ReaderWriterLockSlim direkomendasikan untuk semua pengembangan baru. ReaderWriterLockSlim mirip ReaderWriterLockdengan , tetapi memiliki aturan yang disederhanakan untuk rekursi dan untuk meningkatkan dan menurunkan status kunci. ReaderWriterLockSlim menghindari banyak kasus potensi kebuntuan. Selain itu, performa ReaderWriterLockSlim secara signifikan lebih baik daripada ReaderWriterLock.

ReaderWriterLock digunakan untuk menyinkronkan akses ke sumber daya. Pada waktu tertentu, ini memungkinkan akses baca bersamaan untuk beberapa utas, atau menulis akses untuk satu utas. Dalam situasi di mana sumber daya jarang diubah, memberikan throughput yang ReaderWriterLock lebih baik daripada kunci satu per satu, seperti Monitor.

ReaderWriterLock bekerja paling baik di mana sebagian besar akses dibaca, sementara penulisan jarang dan durasi pendek. Beberapa pembaca bergantian dengan penulis tunggal, sehingga pembaca maupun penulis tidak diblokir untuk jangka waktu yang lama.

Catatan

Memegang kunci pembaca atau kunci penulis untuk waktu yang lama akan membuat utas lain kelaparan. Untuk performa terbaik, pertimbangkan untuk merestrukturisasi aplikasi Anda untuk meminimalkan durasi penulisan.

Utas dapat menahan kunci pembaca atau kunci penulis, tetapi tidak keduanya secara bersamaan. Alih-alih melepaskan kunci pembaca untuk memperoleh kunci penulis, Anda dapat menggunakan UpgradeToWriterLock dan DowngradeFromWriterLock.

Permintaan kunci rekursif meningkatkan jumlah kunci pada kunci.

Pembaca dan penulis diantrekan secara terpisah. Ketika utas melepaskan kunci penulis, semua utas yang menunggu dalam antrean pembaca pada saat itu diberikan kunci pembaca; ketika semua kunci pembaca telah dirilis, utas berikutnya yang menunggu dalam antrean penulis, jika ada, diberikan kunci penulis, dan sebagainya. Dengan kata lain, ReaderWriterLock bergantian antara kumpulan pembaca, dan satu penulis.

Saat utas dalam antrean penulis menunggu kunci pembaca aktif dirilis, utas yang meminta kunci pembaca baru terakumulasi dalam antrean pembaca. Permintaan mereka tidak diberikan, meskipun mereka dapat berbagi akses bersamaan dengan pemegang kunci pembaca yang ada; ini membantu melindungi penulis dari penyumbatan yang tidak terbatas oleh pembaca.

Sebagian besar metode untuk memperoleh kunci pada nilai waktu habis yang ReaderWriterLock diterima. Gunakan waktu habis untuk menghindari kebuntuan di aplikasi Anda. Misalnya, utas mungkin memperoleh kunci penulis pada satu sumber daya lalu meminta kunci pembaca pada sumber daya kedua; sementara itu, utas lain mungkin memperoleh kunci penulis pada sumber daya kedua, dan meminta kunci pembaca pada yang pertama. Kecuali waktu habis digunakan, alur akan mengalami kebuntuan.

Jika interval waktu habis kedaluwarsa dan permintaan kunci belum diberikan, metode mengembalikan kontrol ke utas panggilan dengan melempar ApplicationException. Utas dapat menangkap pengecualian ini dan menentukan tindakan apa yang akan diambil berikutnya.

Waktu habis dinyatakan dalam milidetik. Jika Anda menggunakan System.TimeSpan untuk menentukan waktu habis, nilai yang digunakan adalah jumlah total seluruh milidetik yang diwakili oleh TimeSpan. Tabel berikut ini memperlihatkan nilai batas waktu yang valid dalam milidetik.

Nilai	Deskripsi
-1	Utas menunggu sampai kunci diperoleh, terlepas dari berapa lama waktu yang dibutuhkan. Untuk metode yang menentukan batas waktu bilangan bulat, konstanta Infinite dapat digunakan.
0	Utas tidak menunggu untuk memperoleh kunci. Jika kunci tidak dapat segera diperoleh, metode akan kembali.
>0	Jumlah milidetik untuk menunggu.

Dengan pengecualian -1, nilai waktu habis negatif tidak diperbolehkan. Jika Anda menentukan bilangan bulat negatif selain -1, nilai waktu habis nol akan digunakan sebagai gantinya. (Artinya, metode kembali tanpa menunggu, jika kunci tidak dapat segera diperoleh.) Jika Anda menentukan TimeSpan yang mewakili jumlah milidetik negatif selain -1, ArgumentOutOfRangeException akan dilemparkan.

Konstruktor

ReaderWriterLock()

Menginisialisasi instans baru kelas ReaderWriterLock.

Properti

IsReaderLockHeld	Mendapatkan nilai yang menunjukkan apakah utas saat ini memegang kunci pembaca.
IsWriterLockHeld	Mendapatkan nilai yang menunjukkan apakah utas saat ini memegang kunci penulis.
WriterSeqNum	Mendapatkan nomor urut saat ini.

Metode

AcquireReaderLock(Int32)	Memperoleh kunci pembaca, menggunakan Int32 nilai untuk waktu habis.
AcquireReaderLock(TimeSpan)	Memperoleh kunci pembaca, menggunakan TimeSpan nilai untuk waktu habis.
AcquireWriterLock(Int32)	Memperoleh kunci penulis, menggunakan Int32 nilai untuk waktu habis.
AcquireWriterLock(TimeSpan)	Memperoleh kunci penulis, menggunakan TimeSpan nilai untuk waktu habis.
AnyWritersSince(Int32)	Menunjukkan apakah kunci penulis telah diberikan ke utas apa pun sejak nomor urut diperoleh.
DowngradeFromWriterLock(LockCookie)	Memulihkan status kunci utas ke apa yang sebelumnya UpgradeToWriterLock(Int32) dipanggil.
Equals(Object)	Menentukan apakah objek yang ditentukan sama dengan objek saat ini. (Diperoleh dari Object)
GetHashCode()	Berfungsi sebagai fungsi hash default. (Diperoleh dari Object)
GetType()	Mendapatkan instans Type saat ini. (Diperoleh dari Object)
MemberwiseClone()	Membuat salinan dangkal dari yang saat ini Object. (Diperoleh dari Object)
ReleaseLock()	Melepaskan kunci, terlepas dari berapa kali utas memperoleh kunci.
ReleaseReaderLock()	Mengurangi jumlah kunci.
ReleaseWriterLock()	Mengurangi jumlah kunci pada kunci penulis.
RestoreLock(LockCookie)	Memulihkan status kunci utas ke apa yang sebelum memanggil ReleaseLock().
ToString()	Mengembalikan string yang mewakili objek saat ini. (Diperoleh dari Object)
UpgradeToWriterLock(Int32)	Meningkatkan kunci pembaca ke kunci penulis, menggunakan Int32 nilai untuk waktu habis.
UpgradeToWriterLock(TimeSpan)	Meningkatkan kunci pembaca ke kunci penulis, menggunakan TimeSpan nilai untuk waktu habis.

Keamanan Thread

Jenis ini aman untuk utas.

Lihat juga

• Pengaluran Terkelola
• ReaderWriterLock