LockRecursionException Class

The exception that is thrown when recursive entry into a lock is not compatible with the recursion policy for the lock.

System.Object
  System.Exception
    System.Threading.LockRecursionException

Namespace:  System.Threading
Assemblies:   System.Threading (in System.Threading.dll)
  mscorlib (in mscorlib.dll)

public class LockRecursionException : Exception

The LockRecursionException type exposes the following members.

  NameDescription
Public methodSupported by Portable Class LibrarySupported in .NET for Windows Store appsLockRecursionException()Initializes a new instance of the LockRecursionException class with a system-supplied message that describes the error.
Public methodSupported by Portable Class LibrarySupported in .NET for Windows Store appsLockRecursionException(String)Initializes a new instance of the LockRecursionException class with a specified message that describes the error.
Protected methodLockRecursionException(SerializationInfo, StreamingContext)Initializes a new instance of the LockRecursionException class with serialized data.
Public methodSupported by Portable Class LibrarySupported in .NET for Windows Store appsLockRecursionException(String, Exception)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.
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  NameDescription
Public propertySupported by Portable Class LibrarySupported in .NET for Windows Store appsDataGets a collection of key/value pairs that provide additional user-defined information about the exception. (Inherited from Exception.)
Public propertySupported by Portable Class LibrarySupported in .NET for Windows Store appsHelpLinkGets or sets a link to the help file associated with this exception. (Inherited from Exception.)
Public propertySupported by Portable Class LibrarySupported in .NET for Windows Store appsHResultGets or sets HRESULT, a coded numerical value that is assigned to a specific exception. (Inherited from Exception.)
Public propertySupported by Portable Class LibrarySupported in .NET for Windows Store appsInnerExceptionGets the Exception instance that caused the current exception. (Inherited from Exception.)
Public propertySupported by Portable Class LibrarySupported in .NET for Windows Store appsMessageGets a message that describes the current exception. (Inherited from Exception.)
Public propertySupported by Portable Class LibrarySupported in .NET for Windows Store appsSourceGets or sets the name of the application or the object that causes the error. (Inherited from Exception.)
Public propertySupported by Portable Class LibrarySupported in .NET for Windows Store appsStackTraceGets a string representation of the immediate frames on the call stack. (Inherited from Exception.)
Public propertyTargetSiteGets the method that throws the current exception. (Inherited from Exception.)
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  NameDescription
Public methodSupported by Portable Class LibrarySupported in .NET for Windows Store appsEquals(Object)Determines whether the specified object is equal to the current object. (Inherited from Object.)
Protected methodSupported by Portable Class LibrarySupported in .NET for Windows Store appsFinalizeAllows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public methodSupported by Portable Class LibrarySupported in .NET for Windows Store appsGetBaseExceptionWhen overridden in a derived class, returns the Exception that is the root cause of one or more subsequent exceptions. (Inherited from Exception.)
Public methodSupported by Portable Class LibrarySupported in .NET for Windows Store appsGetHashCodeServes as the default hash function. (Inherited from Object.)
Public methodGetObjectDataWhen overridden in a derived class, sets the SerializationInfo with information about the exception. (Inherited from Exception.)
Public methodGetTypeGets the runtime type of the current instance. (Inherited from Exception.)
Protected methodSupported by Portable Class LibrarySupported in .NET for Windows Store appsMemberwiseCloneCreates a shallow copy of the current Object. (Inherited from Object.)
Public methodSupported by Portable Class LibrarySupported in .NET for Windows Store appsToStringCreates and returns a string representation of the current exception. (Inherited from Exception.)
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  NameDescription
Protected eventSerializeObjectStateOccurs when an exception is serialized to create an exception state object that contains serialized data about the exception. (Inherited from Exception.)
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LockRecursionException is thrown for several reasons, including the following:

  • If a thread tries to enter an instance of ReaderWriterLockSlim recursively, but the instance does not support recursion.

  • 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. This represents a potential deadlock and therefore is not allowed.

  • If allowing one more level of recursion would exceed the maximum value for the internal storage counter used to track recursions. This limit is so large that applications should never encounter it.

The following example shows two causes of LockRecursionException when using the ReaderWriterLockSlim class. The program creates a ReaderWriterLockSlim by using the default constructor, which disallows recursion. The program then starts a thread that enters the lock in read mode. The thread tries to enter the lock recursively in read mode, and catches the resulting exception. Finally, the thread tries to enter write mode, which would create a potential for deadlocks. 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.
 */

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

.NET for Windows Store apps

Supported in: Windows 8

Supported in: Windows Phone 8.1

Supported in: Windows Phone Silverlight 8.1

Supported in: Windows Phone Silverlight 8

Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.
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