SafeWaitHandle 类

定义

命名空间:

Microsoft.Win32.SafeHandles

程序集:

netstandard.dll, System.Runtime.dll

Source:

SafeWaitHandle.cs

表示等待句柄的包装类。

public ref class SafeWaitHandle sealed : Microsoft::Win32::SafeHandles::SafeHandleZeroOrMinusOneIsInvalid

public sealed class SafeWaitHandle : Microsoft.Win32.SafeHandles.SafeHandleZeroOrMinusOneIsInvalid

type SafeWaitHandle = class
    inherit SafeHandleZeroOrMinusOneIsInvalid

Public NotInheritable Class SafeWaitHandle
Inherits SafeHandleZeroOrMinusOneIsInvalid

继承

Object

CriticalFinalizerObject

SafeHandle

SafeHandleZeroOrMinusOneIsInvalid

SafeWaitHandle

示例

下面的代码示例演示如何使用互操作通过类和非托管SafeWaitHandle函数创建互斥体CreateMutex。

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

class SafeHandlesExample
{
    static void Main()
    {
        UnmanagedMutex uMutex = new("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.");
        }
    }
}

partial class UnmanagedMutex(string Name)
{
    // Use interop to call the CreateMutex function.
    [LibraryImport("kernel32.dll", EntryPoint = "CreateMutexW", StringMarshalling = StringMarshalling.Utf16)]
    private static partial SafeWaitHandle CreateMutex(
        IntPtr lpMutexAttributes,
        [MarshalAs(UnmanagedType.Bool)] bool bInitialOwner,
        string lpName
        );

    // Use interop to call the ReleaseMutex function.
    // For more information about ReleaseMutex,
    // see the unmanaged MSDN reference library.
    [LibraryImport("kernel32.dll")]
    [return: MarshalAs(UnmanagedType.Bool)]
    public static partial bool ReleaseMutex(SafeWaitHandle hMutex);

    private SafeWaitHandle _handleValue = null;
    private readonly IntPtr _mutexAttrValue = IntPtr.Zero;
    private string nameValue = Name;

    public void Create()
    {
        ArgumentException.ThrowIfNullOrEmpty(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 (!_handleValue.IsInvalid)
            {
                return _handleValue;
            }
            else
            {
                return null;
            }
        }
    }

    public string Name => nameValue;

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

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

注解

该 SafeWaitHandle 类由 System.Threading.WaitHandle 该类使用。 它是 Win32 互斥体和自动和手动重置事件的包装器。

Important

此类型实现 IDisposable 接口。 使用完该类型后，应直接或间接处理它。 若要直接释放类型，请在块中Disposetry/调用其catch方法。 若要间接释放它，请使用语言构造，例如 using （在 C# 中）或 Using （在 Visual Basic 中）。

构造函数

名称	说明
SafeWaitHandle()	创建 SafeWaitHandle。
SafeWaitHandle(IntPtr, Boolean)	初始化 SafeWaitHandle 类的新实例。

字段

名称	说明
handle	指定要包装的句柄。 (继承自 SafeHandle)

属性

名称	说明
IsClosed	获取一个值，该值指示句柄是否关闭。 (继承自 SafeHandle)
IsInvalid	获取一个值，该值指示句柄是否无效。 (继承自 SafeHandleZeroOrMinusOneIsInvalid)

方法

名称	说明
Close()	标记释放和释放资源的句柄。 (继承自 SafeHandle)
DangerousAddRef(Boolean)	手动递增实例上的 SafeHandle 引用计数器。 (继承自 SafeHandle)
DangerousGetHandle()	返回字段的值 handle 。 (继承自 SafeHandle)
DangerousRelease()	手动递减实例上的 SafeHandle 引用计数器。 (继承自 SafeHandle)
Dispose()	释放类使用 SafeHandle 的所有资源。 (继承自 SafeHandle)
Dispose(Boolean)	释放类使用 SafeHandle 的非托管资源，该类指定是否执行正常释放操作。 (继承自 SafeHandle)
Equals(Object)	确定指定的对象是否等于当前对象。 (继承自 Object)
GetHashCode()	用作默认哈希函数。 (继承自 Object)
GetType()	获取当前实例的 Type。 (继承自 Object)
MemberwiseClone()	创建当前 Object的浅表副本。 (继承自 Object)
ReleaseHandle()	在派生类中重写时，执行释放句柄所需的代码。 (继承自 SafeHandle)
SetHandle(IntPtr)	将句柄设置为指定的预先存在的句柄。 (继承自 SafeHandle)
SetHandleAsInvalid()	将句柄标记为不再使用。 (继承自 SafeHandle)
ToString()	返回一个表示当前对象的字符串。 (继承自 Object)

另请参阅

• SafeHandleZeroOrMinusOneIsInvalid
• WaitHandle
• Mutex
• AutoResetEvent
• ManualResetEvent