SafeWaitHandle 构造函数

定义

命名空间:

Microsoft.Win32.SafeHandles

程序集:

System.Runtime.dll

重载

SafeWaitHandle()	创建一个 SafeWaitHandle。
SafeWaitHandle(IntPtr, Boolean)	初始化 SafeWaitHandle 类的新实例。

SafeWaitHandle()

Source:

SafeWaitHandle.cs

创建一个 SafeWaitHandle。

public:
 SafeWaitHandle();

public SafeWaitHandle ();

Public Sub New ()

SafeWaitHandle(IntPtr, Boolean)

Source:

SafeWaitHandle.cs

初始化 SafeWaitHandle 类的新实例。

public:
 SafeWaitHandle(IntPtr existingHandle, bool ownsHandle);

public SafeWaitHandle (IntPtr existingHandle, bool ownsHandle);

new Microsoft.Win32.SafeHandles.SafeWaitHandle : nativeint * bool -> Microsoft.Win32.SafeHandles.SafeWaitHandle

Public Sub New (existingHandle As IntPtr, ownsHandle As Boolean)

参数

existingHandle

IntPtr

nativeint

IntPtr 对象，表示要使用的预先存在的句柄。

ownsHandle

Boolean

若要在终止阶段可靠地释放此句柄，则为 true；若要阻止可靠释放（不建议使用），则为 false。

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CreateMutex函数创建互斥SafeWaitHandle体。

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 IntPtr CreateMutex(IntPtr lpMutexAttributes, bool bInitialOwner,
   string lpName);

    [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");
        }

         IntPtr ptr = CreateMutex(mutexAttrValue,
                                        true, nameValue);

         handleValue = new SafeWaitHandle(ptr, true);

         // 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 IntPtr

    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

        Dim ptr As IntPtr = CreateMutex(mutexAttrValue, True, nameValue)

        handleValue = New SafeWaitHandle(ptr, True)

        ' 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

另请参阅

• SafeHandleZeroOrMinusOneIsInvalid
• SafeHandle