SafeWaitHandle 類別

定義

命名空間:

Microsoft.Win32.SafeHandles

組件:

System.Runtime.dll

來源:

SafeWaitHandle.cs

代表等候控制代碼的包裝函式類別。

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

下列程式代碼範例示範如何使用 Interop，使用 SafeWaitHandle 類別和 Unmanaged 函 CreateMutex 式建立 Mutex。

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 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

類別 SafeWaitHandle 會使用 System.Threading.WaitHandle 類別。 它是 Win32 Mutex 和自動和手動重設事件的包裝函式。

重要

此型別代表 IDisposable 介面。 當您完成使用型別時，您應該直接或間接處置它。 若要直接處置型別，請呼叫其 try/catch 區塊中的 Dispose 方法。 若要間接處置它，請使用語言建構函式，例如 using (在 C# 中) 或 Using (在 Visual Basic 中)。 如需詳細資訊，請參閱 IDisposable 介面文章中的＜使用實作 IDisposable 的物件＞一節。

建構函式

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

欄位

handle

指定要包裝的控制代碼。 (繼承來源 SafeHandle)

屬性

IsClosed	取得值，指出控制代碼是否已關閉。 (繼承來源 SafeHandle)
IsInvalid	取得值，表示控制代碼是否無效。 (繼承來源 SafeHandleZeroOrMinusOneIsInvalid)

方法

Close()	標記要釋出和釋放資源的控制代碼。 (繼承來源 SafeHandle)
DangerousAddRef(Boolean)	手動遞增 SafeHandle 執行個體上的參考計數器。 (繼承來源 SafeHandle)
DangerousGetHandle()	傳回 handle 欄位的值。 (繼承來源 SafeHandle)
DangerousRelease()	手動遞減 SafeHandle 執行個體上的參考計數器。 (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 SafeHandle 類別所使用的 Unmanaged 資源，指定是否要執行一般處置作業。 (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()	做為預設雜湊函式。 (繼承來源 Object)
GetType()	取得目前執行個體的 Type。 (繼承來源 Object)
MemberwiseClone()	建立目前 Object 的淺層複製。 (繼承來源 Object)
ReleaseHandle()	在衍生類別中覆寫時，執行釋放控制代碼所需的程式碼。 (繼承來源 SafeHandle)
SetHandle(IntPtr)	將控制代碼設定為指定的既有控制代碼。 (繼承來源 SafeHandle)
SetHandleAsInvalid()	將控制代碼標記為不再使用。 (繼承來源 SafeHandle)
ToString()	傳回代表目前物件的字串。 (繼承來源 Object)

另請參閱

• SafeHandleZeroOrMinusOneIsInvalid
• WaitHandle
• Mutex
• AutoResetEvent
• ManualResetEvent