ThreadStaticAttribute ThreadStaticAttribute ThreadStaticAttribute ThreadStaticAttribute Class

Definición

Indica que el valor de un campo estático es único para cada subproceso.Indicates that the value of a static field is unique for each thread.

public ref class ThreadStaticAttribute : Attribute
[System.AttributeUsage(System.AttributeTargets.Field, Inherited=false)]
[System.Runtime.InteropServices.ComVisible(true)]
[System.Serializable]
public class ThreadStaticAttribute : Attribute
type ThreadStaticAttribute = class
    inherit Attribute
Public Class ThreadStaticAttribute
Inherits Attribute
Herencia
ThreadStaticAttributeThreadStaticAttributeThreadStaticAttributeThreadStaticAttribute
Atributos

Ejemplos

El ejemplo siguiente se crea una instancia de un generador de números aleatorios, crea diez subprocesos además el subproceso principal y, a continuación, genera dos millones de números aleatorios en cada subproceso.The following example instantiates a random number generator, creates ten threads in addition to the main thread, and then generates two million random numbers in each thread. Usa el ThreadStaticAttribute atributo para calcular la suma y el recuento de números aleatorios por subproceso.It uses the ThreadStaticAttribute attribute to calculate the sum and the count of random numbers per thread. También define dos campos adicionales por subproceso, previous y abnormal, que le permite detectar daños en el generador de números aleatorios.It also defines two additional per-thread fields, previous and abnormal, that allows it to detect corruption of the random number generator.

using System;
using System.Threading;

public class Example
{
   [ThreadStatic] static double previous = 0.0;
   [ThreadStatic] static double sum = 0.0;
   [ThreadStatic] static int calls = 0;
   [ThreadStatic] static bool abnormal;
   static int totalNumbers = 0;
   static CountdownEvent countdown;
   private static Object lockObj;
   Random rand;
   
   public Example()
   { 
      rand = new Random();
      lockObj = new Object();
      countdown = new CountdownEvent(1);
   } 

   public static void Main()
   {
      Example ex = new Example();
      Thread.CurrentThread.Name = "Main";
      ex.Execute();
      countdown.Wait();
      Console.WriteLine("{0:N0} random numbers were generated.", totalNumbers);
   }

   private void Execute()
   {   
      for (int threads = 1; threads <= 10; threads++)
      {
         Thread newThread = new Thread(new ThreadStart(this.GetRandomNumbers));
         countdown.AddCount();
         newThread.Name = threads.ToString();
         newThread.Start();
      }
      this.GetRandomNumbers();
   }

   private void GetRandomNumbers()
   {
      double result = 0.0;
      
       
      for (int ctr = 0; ctr < 2000000; ctr++)
      {
         lock (lockObj) {
            result = rand.NextDouble();
            calls++;
            Interlocked.Increment(ref totalNumbers);
            // We should never get the same random number twice.
            if (result == previous) {
               abnormal = true;
               break;
            }
            else {
               previous = result;
               sum += result;
            }   
         }
      }
      // get last result
      if (abnormal)
         Console.WriteLine("Result is {0} in {1}", previous, Thread.CurrentThread.Name);
       
      Console.WriteLine("Thread {0} finished random number generation.", Thread.CurrentThread.Name);
      Console.WriteLine("Sum = {0:N4}, Mean = {1:N4}, n = {2:N0}\n", sum, sum/calls, calls);        
      countdown.Signal();
   }
}
// The example displays output similar to the following:
//    Thread 1 finished random number generation.
//    Total = 1,000,556.7483, Mean = 0.5003, n = 2,000,000
//    
//    Thread 6 finished random number generation.
//    Total = 999,704.3865, Mean = 0.4999, n = 2,000,000
//    
//    Thread 2 finished random number generation.
//    Total = 999,680.8904, Mean = 0.4998, n = 2,000,000
//    
//    Thread 10 finished random number generation.
//    Total = 999,437.5132, Mean = 0.4997, n = 2,000,000
//    
//    Thread 8 finished random number generation.
//    Total = 1,000,663.7789, Mean = 0.5003, n = 2,000,000
//    
//    Thread 4 finished random number generation.
//    Total = 999,379.5978, Mean = 0.4997, n = 2,000,000
//    
//    Thread 5 finished random number generation.
//    Total = 1,000,011.0605, Mean = 0.5000, n = 2,000,000
//    
//    Thread 9 finished random number generation.
//    Total = 1,000,637.4556, Mean = 0.5003, n = 2,000,000
//    
//    Thread Main finished random number generation.
//    Total = 1,000,676.2381, Mean = 0.5003, n = 2,000,000
//    
//    Thread 3 finished random number generation.
//    Total = 999,951.1025, Mean = 0.5000, n = 2,000,000
//    
//    Thread 7 finished random number generation.
//    Total = 1,000,844.5217, Mean = 0.5004, n = 2,000,000
//    
//    22,000,000 random numbers were generated.
Imports System.Threading

Public Class Example
   <ThreadStatic> Shared previous As Double = 0.0
   <ThreadStatic> Shared sum As Double = 0.0
   <ThreadStatic> Shared calls As Integer = 0
   <ThreadStatic> Shared abnormal As Boolean
   Shared totalNumbers As Integer = 0
   Shared countdown As CountdownEvent
   Private Shared lockObj As Object
   Dim rand As Random

   Public Sub New()
      rand = New Random()
      lockObj = New Object()
      countdown = New CountdownEvent(1)
   End Sub

   Public Shared Sub Main()
      Dim ex As New Example()
      Thread.CurrentThread.Name = "Main"
      ex.Execute()
      countdown.Wait()
      Console.WriteLine("{0:N0} random numbers were generated.", totalNumbers)
   End Sub

   Private Sub Execute()
      For threads As Integer = 1 To 10
         Dim newThread As New Thread(New ThreadStart(AddressOf GetRandomNumbers))
         countdown.AddCount()
         newThread.Name = threads.ToString()
         newThread.Start()
      Next
      Me.GetRandomNumbers()
   End Sub

   Private Sub GetRandomNumbers()
      Dim result As Double = 0.0
      
       
      For ctr As Integer = 1 To 2000000
         SyncLock lockObj
            result = rand.NextDouble()
            calls += 1
            Interlocked.Increment(totalNumbers)
            ' We should never get the same random number twice.
            If result = previous Then
               abnormal = True
               Exit For
            Else
               previous = result
               sum += result
            End If   
         End SyncLock
      Next
      ' Get last result.
      If abnormal Then
         Console.WriteLine("Result is {0} in {1}", previous, Thread.CurrentThread.Name)
      End If       
      
      Console.WriteLine("Thread {0} finished random number generation.", Thread.CurrentThread.Name)
      Console.WriteLine("Sum = {0:N4}, Mean = {1:N4}, n = {2:N0}", sum, sum/calls, calls)
      Console.WriteLine()        
      countdown.Signal()
   End Sub
End Class
' The example displays output similar to the following:
'    Thread 1 finished random number generation.
'    Total = 1,000,556.7483, Mean = 0.5003, n = 2,000,000
'    
'    Thread 6 finished random number generation.
'    Total = 999,704.3865, Mean = 0.4999, n = 2,000,000
'    
'    Thread 2 finished random number generation.
'    Total = 999,680.8904, Mean = 0.4998, n = 2,000,000
'    
'    Thread 10 finished random number generation.
'    Total = 999,437.5132, Mean = 0.4997, n = 2,000,000
'    
'    Thread 8 finished random number generation.
'    Total = 1,000,663.7789, Mean = 0.5003, n = 2,000,000
'    
'    Thread 4 finished random number generation.
'    Total = 999,379.5978, Mean = 0.4997, n = 2,000,000
'    
'    Thread 5 finished random number generation.
'    Total = 1,000,011.0605, Mean = 0.5000, n = 2,000,000
'    
'    Thread 9 finished random number generation.
'    Total = 1,000,637.4556, Mean = 0.5003, n = 2,000,000
'    
'    Thread Main finished random number generation.
'    Total = 1,000,676.2381, Mean = 0.5003, n = 2,000,000
'    
'    Thread 3 finished random number generation.
'    Total = 999,951.1025, Mean = 0.5000, n = 2,000,000
'    
'    Thread 7 finished random number generation.
'    Total = 1,000,844.5217, Mean = 0.5004, n = 2,000,000
'    
'    22,000,000 random numbers were generated.

El ejemplo se usa el lock instrucción en C# y el SyncLock construir en Visual Basic para sincronizar el acceso al generador de números aleatorios.The example uses the lock statement in C# and the SyncLock construct in Visual Basic to synchronize access to the random number generator. Esto evita que los daños en el generador de números aleatorios, lo que normalmente produce su devuelve un valor de cero para todas las llamadas subsiguientes.This prevents corruption of the random number generator, which typically results in its returning a value of zero for all subsequent calls.

El ejemplo también usa el CountdownEvent clase para asegurarse de que cada subproceso ha terminado de generar números aleatorios antes de mostrar el número total de llamadas.The example also uses the CountdownEvent class to ensure that each thread has finished generating random numbers before it displays the total number of calls. En caso contrario, si el subproceso principal finaliza su ejecución antes de los subprocesos adicionales que genera, muestra un valor inexacto, el número total de llamadas al método.Otherwise, if the main thread completes execution before the additional threads that it spawns, it displays an inaccurate value for the total number of method calls.

Comentarios

Un static campo marcado con ThreadStaticAttribute no se comparte entre los subprocesos.A static field marked with ThreadStaticAttribute is not shared between threads. Cada subproceso en ejecución tiene una instancia independiente del campo y por separado establece y obtiene los valores para ese campo.Each executing thread has a separate instance of the field, and independently sets and gets values for that field. Si se obtiene acceso al campo en un subproceso diferente, contendrá un valor diferente.If the field is accessed on a different thread, it will contain a different value.

Tenga en cuenta que, además de aplicar el ThreadStaticAttribute atributo a un campo, debe definir también como un static campo (en C#) o un Shared campo (en Visual Basic).Note that in addition to applying the ThreadStaticAttribute attribute to a field, you must also define it as a static field (in C#) or a Shared field (in Visual Basic).

Nota

No especifique los valores iniciales para los campos marcados con ThreadStaticAttribute, porque esa inicialización se produce solo una vez, cuando se ejecuta el constructor de clase y, por tanto, afecta a un solo subproceso.Do not specify initial values for fields marked with ThreadStaticAttribute, because such initialization occurs only once, when the class constructor executes, and therefore affects only one thread. Si no especifica un valor inicial, puede confiar en el campo que se inicializa en su valor predeterminado si es un tipo de valor, o a null si es un tipo de referencia.If you do not specify an initial value, you can rely on the field being initialized to its default value if it is a value type, or to null if it is a reference type.

Utilice este atributo, ya que es y no se derivan de él.Use this attribute as it is, and do not derive from it.

Para obtener más información sobre el uso de atributos, vea atributos.For more information about using attributes, see Attributes.

Constructores

ThreadStaticAttribute() ThreadStaticAttribute() ThreadStaticAttribute() ThreadStaticAttribute()

Inicializa una nueva instancia de la clase ThreadStaticAttribute.Initializes a new instance of the ThreadStaticAttribute class.

Métodos

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

Devuelve un valor que indica si esta instancia es igual que un objeto especificado.Returns a value that indicates whether this instance is equal to a specified object.

(Inherited from Attribute)
GetHashCode() GetHashCode() GetHashCode() GetHashCode()

Devuelve el código hash de esta instancia.Returns the hash code for this instance.

(Inherited from Attribute)
GetType() GetType() GetType() GetType()

Obtiene el Type de la instancia actual.Gets the Type of the current instance.

(Inherited from Object)
IsDefaultAttribute() IsDefaultAttribute() IsDefaultAttribute() IsDefaultAttribute()

Si se reemplaza en una clase derivada, indica si el valor de esta instancia es el valor predeterminado de la clase derivada.When overridden in a derived class, indicates whether the value of this instance is the default value for the derived class.

(Inherited from Attribute)
Match(Object) Match(Object) Match(Object) Match(Object)

Cuando se invalida en una clase derivada, devuelve un valor que indica si esta instancia es igual a un objeto especificado.When overridden in a derived class, returns a value that indicates whether this instance equals a specified object.

(Inherited from Attribute)
MemberwiseClone() MemberwiseClone() MemberwiseClone() MemberwiseClone()

Crea una copia superficial del objeto Object actual.Creates a shallow copy of the current Object.

(Inherited from Object)
ToString() ToString() ToString() ToString()

Devuelve una cadena que representa el objeto actual.Returns a string that represents the current object.

(Inherited from Object)

Implementaciones de interfaz explícitas

_Attribute.GetIDsOfNames(Guid, IntPtr, UInt32, UInt32, IntPtr) _Attribute.GetIDsOfNames(Guid, IntPtr, UInt32, UInt32, IntPtr) _Attribute.GetIDsOfNames(Guid, IntPtr, UInt32, UInt32, IntPtr) _Attribute.GetIDsOfNames(Guid, IntPtr, UInt32, UInt32, IntPtr)

Asigna un conjunto de nombres a un conjunto correspondiente de identificadores de envío.Maps a set of names to a corresponding set of dispatch identifiers.

(Inherited from Attribute)
_Attribute.GetTypeInfo(UInt32, UInt32, IntPtr) _Attribute.GetTypeInfo(UInt32, UInt32, IntPtr) _Attribute.GetTypeInfo(UInt32, UInt32, IntPtr) _Attribute.GetTypeInfo(UInt32, UInt32, IntPtr)

Obtiene la información de tipos de un objeto, que puede utilizarse para obtener la información de tipos de una interfaz.Retrieves the type information for an object, which can be used to get the type information for an interface.

(Inherited from Attribute)
_Attribute.GetTypeInfoCount(UInt32) _Attribute.GetTypeInfoCount(UInt32) _Attribute.GetTypeInfoCount(UInt32) _Attribute.GetTypeInfoCount(UInt32)

Recupera el número de interfaces de información de tipo que proporciona un objeto (0 ó 1).Retrieves the number of type information interfaces that an object provides (either 0 or 1).

(Inherited from Attribute)
_Attribute.Invoke(UInt32, Guid, UInt32, Int16, IntPtr, IntPtr, IntPtr, IntPtr) _Attribute.Invoke(UInt32, Guid, UInt32, Int16, IntPtr, IntPtr, IntPtr, IntPtr) _Attribute.Invoke(UInt32, Guid, UInt32, Int16, IntPtr, IntPtr, IntPtr, IntPtr) _Attribute.Invoke(UInt32, Guid, UInt32, Int16, IntPtr, IntPtr, IntPtr, IntPtr)

Proporciona acceso a las propiedades y los métodos expuestos por un objeto.Provides access to properties and methods exposed by an object.

(Inherited from Attribute)

Propiedades

TypeId TypeId TypeId TypeId

Cuando se implementa en una clase derivada, obtiene un identificador único para este Attribute.When implemented in a derived class, gets a unique identifier for this Attribute.

(Inherited from Attribute)

Se aplica a

Consulte también: