LockRecursionException Class

Definition

當遞迴進入鎖定與鎖定的遞迴原則不相符時,擲回的例外狀況。The exception that is thrown when recursive entry into a lock is not compatible with the recursion policy for the lock.

public ref class LockRecursionException : Exception
public class LockRecursionException : Exception
[System.Serializable]
public class LockRecursionException : Exception
type LockRecursionException = class
    inherit Exception
Public Class LockRecursionException
Inherits Exception
Inheritance
LockRecursionException
Attributes

Examples

下列範例顯示使用 ReaderWriterLockSlim 類別時的兩個 LockRecursionException 原因。The following example shows two causes of LockRecursionException when using the ReaderWriterLockSlim class. 程式會使用無參數的函式建立 ReaderWriterLockSlim,這不允許遞迴。The program creates a ReaderWriterLockSlim by using the parameterless constructor, which disallows recursion. 程式接著會啟動一個進入讀取模式鎖定的執行緒。The program then starts a thread that enters the lock in read mode. 執行緒嘗試以遞迴方式進入讀取模式的鎖定,並捕捉產生的例外狀況。The thread tries to enter the lock recursively in read mode, and catches the resulting exception. 最後,執行緒會嘗試進入寫入模式,這可能會造成鎖死。Finally, the thread tries to enter write mode, which would create a potential for deadlocks. 執行緒會攔截產生的例外狀況。The thread catches the resulting exception.

using System;
using System.Threading;

class Example
{
    // By default, the lock recursion policy for a new 
    // ReaderWriterLockSlim does not allow recursion.
    static ReaderWriterLockSlim rwls = new ReaderWriterLockSlim();

    static void ThreadProc()
    {
        Console.WriteLine("Acquire the reader lock.");
        rwls.EnterReadLock();

        try
        {
            Console.WriteLine("\nAttempt to acquire the reader lock recursively:");
            rwls.EnterReadLock();
        }
        catch (LockRecursionException lre)
        {
            Console.WriteLine("{0}: {1}", 
                lre.GetType().Name, lre.Message);
        }

        try
        {
            Console.WriteLine("\nAttempt to acquire the writer lock recursively:");
            rwls.EnterWriteLock();
        }
        catch (LockRecursionException lre)
        {
            Console.WriteLine("{0}: {1}", 
                lre.GetType().Name, lre.Message);
        }
    }

    static void Main()
    {
        Thread t = new Thread(ThreadProc);
        t.Start();
        t.Join();
    }
}

/* This code example produces output similar to the following:

Acquire the reader lock.

Attempt to acquire the reader lock recursively:
LockRecursionException: Recursive read lock acquisitions not allowed in this mode.

Attempt to acquire the writer lock recursively:
LockRecursionException: Write lock may not be acquired with read lock held. This pattern is prone to deadlocks. Consider using the upgrade lock.
 */
Imports System.Threading

Class Example
    ' By default, the lock recursion policy for a new 
    ' ReaderWriterLockSlim does not allow recursion.
    Private Shared rwls As New ReaderWriterLockSlim()
    
    Shared Sub ThreadProc() 
        Console.WriteLine("Acquire the reader lock.")
        rwls.EnterReadLock()
        
        Try
            Console.WriteLine(vbCrLf & _
                "Attempt to acquire the reader lock recursively:")
            rwls.EnterReadLock()
        Catch lre As LockRecursionException
            Console.WriteLine("{0}: {1}", _
                lre.GetType().Name, lre.Message)
        End Try
        
        Try
            Console.WriteLine(vbCrLf & _
                "Attempt to acquire the writer lock recursively:")
            rwls.EnterWriteLock()
        Catch lre As LockRecursionException
            Console.WriteLine("{0}: {1}", _
                lre.GetType().Name, lre.Message)
        End Try
    
    End Sub 
    
    Shared Sub Main() 

        Dim t As New Thread(AddressOf ThreadProc)
        t.Start()
        t.Join()
    
    End Sub 
End Class 

' This code example produces output similar to the following:
'
'Acquire the reader lock.
'
'Attempt to acquire the reader lock recursively:
'LockRecursionException: Recursive read lock acquisitions not allowed in this mode.
'
'Attempt to acquire the writer lock recursively:
'LockRecursionException: Write lock may not be acquired with read lock held. This pattern is prone to deadlocks. Consider using the upgrade lock.
' 

Remarks

有幾個原因會擲回 LockRecursionException,包括下列各項:LockRecursionException is thrown for several reasons, including the following:

  • 如果執行緒嘗試以遞迴方式輸入 ReaderWriterLockSlim 的實例,但實例不支援遞迴。If a thread tries to enter an instance of ReaderWriterLockSlim recursively, but the instance does not support recursion.

  • 當執行緒最初進入讀取模式的鎖定時,如果執行緒嘗試進入寫入模式或可升級模式下的 ReaderWriterLockSlim 實例。If a thread tries to enter a ReaderWriterLockSlim instance in write mode or upgradeable mode when the thread initially entered the lock in read mode. 這代表潛在的鎖死,因此不允許。This represents a potential deadlock and therefore is not allowed.

  • 如果允許一個以上的遞迴層級,將會超過用來追蹤遞迴之內部儲存體計數器的最大值。If allowing one more level of recursion would exceed the maximum value for the internal storage counter used to track recursions. 此限制值相當大,因此應用程式永遠不會發生這個情形。This limit is so large that applications should never encounter it.

Constructors

LockRecursionException()

使用系統提供的錯誤描述訊息,初始化 LockRecursionException 類別的新執行個體。Initializes a new instance of the LockRecursionException class with a system-supplied message that describes the error.

LockRecursionException(SerializationInfo, StreamingContext)

利用序列化資料,初始化 LockRecursionException 類別的新執行個體。Initializes a new instance of the LockRecursionException class with serialized data.

LockRecursionException(String)

初始化具有指定的錯誤描述訊息之 LockRecursionException 類別的新執行個體。Initializes a new instance of the LockRecursionException class with a specified message that describes the error.

LockRecursionException(String, Exception)

使用指定的錯誤訊息以及造成此例外狀況之內部例外狀況的參考,初始化 LockRecursionException 類別的新執行個體。Initializes a new instance of the LockRecursionException class with a specified error message and a reference to the inner exception that is the cause of this exception.

Properties

Data

取得鍵值組的集合,這些鍵值組會提供關於例外狀況的其他使用者定義資訊。Gets a collection of key/value pairs that provide additional user-defined information about the exception.

(Inherited from Exception)
HelpLink

取得或設定與這個例外狀況相關聯的說明檔連結。Gets or sets a link to the help file associated with this exception.

(Inherited from Exception)
HResult

取得或設定 HRESULT,它是指派給特定例外狀況的編碼數值。Gets or sets HRESULT, a coded numerical value that is assigned to a specific exception.

(Inherited from Exception)
InnerException

取得造成目前例外狀況的 Exception 執行個體。Gets the Exception instance that caused the current exception.

(Inherited from Exception)
Message

取得描述目前例外狀況的訊息。Gets a message that describes the current exception.

(Inherited from Exception)
Source

取得或設定造成錯誤的應用程式或物件的名稱。Gets or sets the name of the application or the object that causes the error.

(Inherited from Exception)
StackTrace

取得呼叫堆疊上即時運算框架的字串表示。Gets a string representation of the immediate frames on the call stack.

(Inherited from Exception)
TargetSite

取得擲回目前例外狀況的方法。Gets the method that throws the current exception.

(Inherited from Exception)

Methods

Equals(Object)

判斷指定的物件是否等於目前的物件。Determines whether the specified object is equal to the current object.

(Inherited from Object)
GetBaseException()

在衍生類別中覆寫時,傳回一或多個後續的例外狀況的根本原因 ExceptionWhen overridden in a derived class, returns the Exception that is the root cause of one or more subsequent exceptions.

(Inherited from Exception)
GetHashCode()

做為預設雜湊函式。Serves as the default hash function.

(Inherited from Object)
GetObjectData(SerializationInfo, StreamingContext)

在衍生類別中覆寫時,使用例外狀況的資訊設定 SerializationInfoWhen overridden in a derived class, sets the SerializationInfo with information about the exception.

(Inherited from Exception)
GetType()

取得目前執行個體的執行階段類型。Gets the runtime type of the current instance.

(Inherited from Exception)
MemberwiseClone()

建立目前 Object 的淺層複製。Creates a shallow copy of the current Object.

(Inherited from Object)
ToString()

建立並傳回目前例外狀況的字串表示。Creates and returns a string representation of the current exception.

(Inherited from Exception)

Events

SerializeObjectState

當例外狀況序列化,以建立包含例外狀況相關序列化資料的例外狀況狀態物件時,就會發生此事件。Occurs when an exception is serialized to create an exception state object that contains serialized data about the exception.

(Inherited from Exception)

Applies to

See also