SafeWaitHandle SafeWaitHandle SafeWaitHandle SafeWaitHandle Class

Definição

Representa uma classe wrapper para um identificador de espera.Represents a wrapper class for a wait handle.

public ref class SafeWaitHandle sealed : Microsoft::Win32::SafeHandles::SafeHandleZeroOrMinusOneIsInvalid
[System.Security.SecurityCritical]
public sealed class SafeWaitHandle : Microsoft.Win32.SafeHandles.SafeHandleZeroOrMinusOneIsInvalid
type SafeWaitHandle = class
    inherit SafeHandleZeroOrMinusOneIsInvalid
Public NotInheritable Class SafeWaitHandle
Inherits SafeHandleZeroOrMinusOneIsInvalid
Herança
Atributos

Exemplos

O exemplo de código a seguir demonstra como usar a interoperabilidade para criar um mutex usando o SafeWaitHandle classe e não gerenciado CreateMutex função.The following code example demonstrates how to use interop to create a mutex using the SafeWaitHandle class and the unmanaged CreateMutex function.

using System;
using Microsoft.Win32.SafeHandles;
using System.Runtime.InteropServices;


class SafeHandlesExample
{

    static void Main()
    {
        UnmanagedMutex uMutex = new UnmanagedMutex("YourCompanyName_SafeHandlesExample_MUTEX");

        try
        {

            uMutex.Create();
            Console.WriteLine("Mutex created. Press Enter to release it.");
            Console.ReadLine();


        }
        catch (Exception e)
        {
            Console.WriteLine(e);
        }
        finally
        {
            uMutex.Release();
            Console.WriteLine("Mutex Released.");
        }

        Console.ReadLine();


    }
}

class UnmanagedMutex 
{


    // Use interop to call the CreateMutex function.
    // For more information about CreateMutex,
    // see the unmanaged MSDN reference library.
    [DllImport("kernel32.dll", CharSet=CharSet.Unicode)]
    static extern SafeWaitHandle CreateMutex(IntPtr lpMutexAttributes, bool bInitialOwner,
    string lpName);


    // Use interop to call the ReleaseMutex function.
    // For more information about ReleaseMutex,
    // see the unmanaged MSDN reference library.
    [DllImport("kernel32.dll")]
    public static extern bool ReleaseMutex(SafeWaitHandle hMutex);



    private SafeWaitHandle handleValue = null;
    private IntPtr mutexAttrValue = IntPtr.Zero;
    private string nameValue = null;

    public UnmanagedMutex(string Name)
    {
        nameValue = Name;
    }


    public void Create()
    {
        if (nameValue == null && nameValue.Length == 0)
        {
            throw new ArgumentNullException("nameValue");
        }

        handleValue = CreateMutex(mutexAttrValue,
                                        true, nameValue);

        // If the handle is invalid,
        // get the last Win32 error 
        // and throw a Win32Exception.
        if (handleValue.IsInvalid)
        {
            Marshal.ThrowExceptionForHR(Marshal.GetHRForLastWin32Error());
        }
    }

    public SafeWaitHandle Handle
    {
        get
        {
            // If the handle is valid,
            // return it.
            if (!handleValue.IsInvalid)
            {
                return handleValue;
            }
            else
            {
                return null;
            }
        }

    }

    public string Name
    {
        get
        {
            return nameValue;
        }

    }


    public void Release()
    {
        ReleaseMutex(handleValue);
    }

}
Imports System
Imports Microsoft.Win32.SafeHandles
Imports System.Runtime.InteropServices

Class SafeHandlesExample


    Shared Sub Main()
        Dim uMutex As New UnmanagedMutex("YourCompanyName_SafeHandlesExample_MUTEX")

        Try

            uMutex.Create()
            Console.WriteLine("Mutex created. Press Enter to release it.")
            Console.ReadLine()


        Catch e As Exception
            Console.WriteLine(e)
        Finally
            uMutex.Release()
            Console.WriteLine("Mutex Released.")
        End Try

        Console.ReadLine()

    End Sub
End Class


Class UnmanagedMutex



    ' Use interop to call the CreateMutex function.
    ' For more information about CreateMutex,
    ' see the unmanaged MSDN reference library.
    <DllImport("kernel32.dll", CharSet:=CharSet.Unicode)> _
    Shared Function CreateMutex(ByVal lpMutexAttributes As IntPtr, ByVal bInitialOwner As Boolean, ByVal lpName As String) As SafeWaitHandle

    End Function



    ' Use interop to call the ReleaseMutex function.
    ' For more information about ReleaseMutex,
    ' see the unmanaged MSDN reference library.
    <DllImport("kernel32.dll")> _
    Public Shared Function ReleaseMutex(ByVal hMutex As SafeWaitHandle) As Boolean

    End Function



    Private handleValue As SafeWaitHandle = Nothing
    Private mutexAttrValue As IntPtr = IntPtr.Zero
    Private nameValue As String = Nothing


    Public Sub New(ByVal Name As String)
        nameValue = Name

    End Sub



    Public Sub Create()
        If nameValue Is Nothing AndAlso nameValue.Length = 0 Then
            Throw New ArgumentNullException("nameValue")
        End If

        handleValue = CreateMutex(mutexAttrValue, True, nameValue)

        ' If the handle is invalid,
        ' get the last Win32 error 
        ' and throw a Win32Exception.
        If handleValue.IsInvalid Then
            Marshal.ThrowExceptionForHR(Marshal.GetHRForLastWin32Error())
        End If

    End Sub


    Public ReadOnly Property Handle() As SafeWaitHandle
        Get
            ' If the handle is valid,
            ' return it.
            If Not handleValue.IsInvalid Then
                Return handleValue
            Else
                Return Nothing
            End If
        End Get
    End Property


    Public ReadOnly Property Name() As String
        Get
            Return nameValue
        End Get
    End Property



    Public Sub Release()
        ReleaseMutex(handleValue)

    End Sub
End Class

Comentários

O SafeWaitHandle classe é usada pelo System.Threading.WaitHandle classe.The SafeWaitHandle class is used by the System.Threading.WaitHandle class. É um wrapper para mutexes de Win32 e automático e eventos de redefinição manual.It is a wrapper for Win32 mutexes and auto and manual reset events.

Importante

Esse tipo implementa o IDisposable interface.This type implements the IDisposable interface. Quando você terminar de usar o tipo, você deve descartá-lo diretamente ou indiretamente.When you have finished using the type, you should dispose of it either directly or indirectly. Para descartar o tipo diretamente, chame seu Dispose método em um try / catch bloco.To dispose of the type directly, call its Dispose method in a try/catch block. Para descartá-los indiretamente, usar uma construção de linguagem, como using (em C#) ou Using (no Visual Basic).To dispose of it indirectly, use a language construct such as using (in C#) or Using (in Visual Basic). Para obter mais informações, consulte a seção "Usando um objeto que implementa IDisposable" o IDisposable tópico da interface.For more information, see the "Using an Object that Implements IDisposable" section in the IDisposable interface topic.

Construtores

SafeWaitHandle(IntPtr, Boolean) SafeWaitHandle(IntPtr, Boolean) SafeWaitHandle(IntPtr, Boolean) SafeWaitHandle(IntPtr, Boolean)

Inicializa uma nova instância da classe SafeWaitHandle.Initializes a new instance of the SafeWaitHandle class.

Propriedades

IsClosed IsClosed IsClosed IsClosed

Obtém um valor que indica se o identificador está fechado.Gets a value indicating whether the handle is closed.

(Inherited from SafeHandle)
IsInvalid IsInvalid IsInvalid IsInvalid

Obtém um valor que indica se o identificador é inválido.Gets a value that indicates whether the handle is invalid.

Métodos

Close() Close() Close() Close()

Marca o identificador de liberação de recursos.Marks the handle for releasing and freeing resources.

(Inherited from SafeHandle)
DangerousAddRef(Boolean) DangerousAddRef(Boolean) DangerousAddRef(Boolean) DangerousAddRef(Boolean)

Incrementa manualmente o contador de referências em instâncias do SafeHandle.Manually increments the reference counter on SafeHandle instances.

(Inherited from SafeHandle)
DangerousGetHandle() DangerousGetHandle() DangerousGetHandle() DangerousGetHandle()

Retorna o valor do campo handle.Returns the value of the handle field.

(Inherited from SafeHandle)
DangerousRelease() DangerousRelease() DangerousRelease() DangerousRelease()

Diminui manualmente o contador de referência em uma instância SafeHandle.Manually decrements the reference counter on a SafeHandle instance.

(Inherited from SafeHandle)
Dispose() Dispose() Dispose() Dispose()

Libera todos os recursos usados pela classe SafeHandle.Releases all resources used by the SafeHandle class.

(Inherited from SafeHandle)
Dispose(Boolean) Dispose(Boolean) Dispose(Boolean) Dispose(Boolean)

Libera os recursos não gerenciados usados pela classe SafeHandle que especifica se deve executar uma operação de descarte normal.Releases the unmanaged resources used by the SafeHandle class specifying whether to perform a normal dispose operation.

(Inherited from SafeHandle)
Equals(Object) Equals(Object) Equals(Object) Equals(Object)

Determina se o objeto especificado é igual ao objeto atual.Determines whether the specified object is equal to the current object.

(Inherited from Object)
GetHashCode() GetHashCode() GetHashCode() GetHashCode()

Serve como a função de hash padrão.Serves as the default hash function.

(Inherited from Object)
GetType() GetType() GetType() GetType()

Obtém o Type da instância atual.Gets the Type of the current instance.

(Inherited from Object)
MemberwiseClone() MemberwiseClone() MemberwiseClone() MemberwiseClone()

Cria uma cópia superficial do Object atual.Creates a shallow copy of the current Object.

(Inherited from Object)
ReleaseHandle() ReleaseHandle() ReleaseHandle() ReleaseHandle()

Quando substituído em uma classe derivada, executa o código necessário para liberar o identificador.When overridden in a derived class, executes the code required to free the handle.

(Inherited from SafeHandle)
SetHandle(IntPtr) SetHandle(IntPtr) SetHandle(IntPtr) SetHandle(IntPtr)

Define o identificador para o identificador pré-existente especificado.Sets the handle to the specified pre-existing handle.

(Inherited from SafeHandle)
SetHandleAsInvalid() SetHandleAsInvalid() SetHandleAsInvalid() SetHandleAsInvalid()

Marca um identificador como não mais usado.Marks a handle as no longer used.

(Inherited from SafeHandle)
ToString() ToString() ToString() ToString()

Retorna uma cadeia de caracteres que representa o objeto atual.Returns a string that represents the current object.

(Inherited from Object)

Campos

handle handle handle handle

Especifica o identificador a ser encapsulado.Specifies the handle to be wrapped.

(Inherited from SafeHandle)

Segurança

SecurityCriticalAttribute
requer confiança total para o chamador imediato.requires full trust for the immediate caller. Este membro não pode ser usado pelo código transparente ou parcialmente confiável.This member cannot be used by partially trusted or transparent code.

Aplica-se a

Veja também