SafeWaitHandle 類別

定義

命名空間:

Microsoft.Win32.SafeHandles

組件:

netstandard.dll, System.Runtime.dll

來源:

SafeWaitHandle.cs

代表等待句柄的包裝類別。

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

繼承

Object

CriticalFinalizerObject

SafeHandle

SafeHandleZeroOrMinusOneIsInvalid

SafeWaitHandle

範例

以下程式碼範例示範如何利用 interop 來利用 SafeWaitHandle 類別與非管理 CreateMutex 函式建立互斥體。

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

備註

SafeWaitHandle該類別由該類別使用System.Threading.WaitHandle。 它是 Win32 互斥組織以及自動和手動重置事件的封裝器。

Important

此類型會實作 IDisposable 介面。 當您完成使用這個物品後，應直接或間接地處理它。 若要直接處置類型，請在 Disposetry/ 區塊中呼叫其 catch 方法。 若要間接處置它，請使用語言建構，例如 using （C#） 或 Using （在 Visual Basic 中）。

建構函式

名稱	Description
SafeWaitHandle()	建立 SafeWaitHandle。
SafeWaitHandle(IntPtr, Boolean)	初始化 SafeWaitHandle 類別的新執行個體。

欄位

名稱	Description
handle	指定要包裹的把手。 (繼承來源 SafeHandle)

屬性

名稱	Description
IsClosed	會得到一個值，表示把柄是否已關閉。 (繼承來源 SafeHandle)
IsInvalid	會得到一個值，表示該句柄是否無效。 (繼承來源 SafeHandleZeroOrMinusOneIsInvalid)

方法

名稱	Description
Close()	標記釋放與釋放資源的把手。 (繼承來源 SafeHandle)
DangerousAddRef(Boolean)	手動遞增參考計數器。SafeHandle (繼承來源 SafeHandle)
DangerousGetHandle()	回傳欄位的 handle 值。 (繼承來源 SafeHandle)
DangerousRelease()	手動減少實例的 SafeHandle 參考計數器。 (繼承來源 SafeHandle)
Dispose()	釋放 SafeHandle 類別所使用的所有資源。 (繼承來源 SafeHandle)
Dispose(Boolean)	釋放類別所使用的 SafeHandle 未管理資源，指定是否執行正常處置操作。 (繼承來源 SafeHandle)
Equals(Object)	判斷指定的物件是否等於目前的物件。 (繼承來源 Object)
GetHashCode()	做為預設哈希函式。 (繼承來源 Object)
GetType()	取得目前實例的 Type。 (繼承來源 Object)
MemberwiseClone()	建立目前 Object的淺層複本。 (繼承來源 Object)
ReleaseHandle()	當在衍生類別中覆寫時，會執行釋放 handle 所需的程式碼。 (繼承來源 SafeHandle)
SetHandle(IntPtr)	將 handle 設為指定的既存 handle。 (繼承來源 SafeHandle)
SetHandleAsInvalid()	標記一個不再使用的把手。 (繼承來源 SafeHandle)
ToString()	傳回表示目前 物件的字串。 (繼承來源 Object)

另請參閱

• SafeHandleZeroOrMinusOneIsInvalid
• WaitHandle
• Mutex
• AutoResetEvent
• ManualResetEvent