ReaderWriterLock.AcquireWriterLock 方法

定義

命名空間:: System.Threading

組件:: netstandard.dll, System.Threading.dll

組件:: System.Threading.dll

組件:: mscorlib.dll

組件:: netstandard.dll

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。

取得作家鎖定。

多載

名稱	Description
AcquireWriterLock(Int32)	取得寫入鎖定，並使用一個 Int32 逾時值。
AcquireWriterLock(TimeSpan)	取得寫入鎖，並使用 TimeSpan 逾時值。

AcquireWriterLock(Int32)

來源:: ReaderWriterLock.cs

來源:: ReaderWriterLock.cs

來源:: ReaderWriterLock.cs

來源:: ReaderWriterLock.cs

來源:: ReaderWriterLock.cs

取得寫入鎖定，並使用一個 Int32 逾時值。

public:
 void AcquireWriterLock(int millisecondsTimeout);

public void AcquireWriterLock(int millisecondsTimeout);

member this.AcquireWriterLock : int -> unit

Public Sub AcquireWriterLock (millisecondsTimeout As Integer)

參數

millisecondsTimeout: Int32

時間只需毫秒。

例外狀況

ApplicationException

millisecondsTimeout 在鎖申請獲准前就已過期。

範例

以下程式碼範例展示了如何取得並釋放寫入鎖定，以及如何處理請求逾時拋出的例外。

此程式碼是該類別更大 ReaderWriterLock 範例的一部分。

// 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;

' 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

// 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);
   }
}

' 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

End Module

備註

此方法會阻塞其他執行緒是否有讀取鎖或寫入鎖。關於寫入鎖與多個並行讀取鎖交替運作的描述，請參見類別。ReaderWriterLock

已經有讀取鎖的執行緒可以透過兩種方式取得寫入鎖：在呼叫 AcquireWriterLock前釋放讀取鎖，或呼叫 UpgradeToWriterLock。

Caution

如果執行緒在仍處於讀取鎖定狀態時呼叫 AcquireWriterLock ，則會封鎖自己的讀取鎖定;若指定無限逾時，執行緒將陷入死結。為避免此類死結，請使用 IsReaderLockHeld 來判斷目前執行緒是否已經有讀取鎖定。

AcquireWriterLock 支援遞迴寫入鎖定請求。也就是說，執行緒可以多次呼叫 AcquireWriterLock ，每次都會增加鎖的數量。你必須為每次撥打ReleaseWriterLock電話撥打AcquireWriterLock一次。或者，你也可以立即打電話 ReleaseLock 將鎖數降為零。

遞迴鎖請求總是立即被授予，且不會將請求執行緒放入寫入佇列。

關於有效的逾時值，請參見 ReaderWriterLock。

另請參閱

管理的執行緒

適用於

AcquireWriterLock(TimeSpan)

來源:: ReaderWriterLock.cs

來源:: ReaderWriterLock.cs

來源:: ReaderWriterLock.cs

來源:: ReaderWriterLock.cs

來源:: ReaderWriterLock.cs

取得寫入鎖，並使用 TimeSpan 逾時值。

public:
 void AcquireWriterLock(TimeSpan timeout);

public void AcquireWriterLock(TimeSpan timeout);

member this.AcquireWriterLock : TimeSpan -> unit

Public Sub AcquireWriterLock (timeout As TimeSpan)

參數

timeout: TimeSpan

那是 TimeSpan 指定暫停期間的。

例外狀況

ApplicationException

timeout 在鎖申請獲准前就已過期。

ArgumentOutOfRangeException

timeout 指定除 -1 毫秒外的負值。

備註