IDisposable.Dispose Yöntem

Tanım

Yönetilmeyen kaynakları boşaltma, serbest bırakma veya sıfırlama ile ilişkili uygulama tanımlı görevleri gerçekleştirir.Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.

public:
 void Dispose();
public void Dispose ();
abstract member Dispose : unit -> unit
Public Sub Dispose ()

Örnekler

Aşağıdaki örnek, Dispose yöntemini nasıl uygulayabileceğinizi gösterir.The following example shows how you can implement the Dispose method.

#using <System.dll>
#using <System.Windows.Forms.dll>

using namespace System;
using namespace System::ComponentModel;
using namespace System::Windows::Forms;

// The following example demonstrates how to create a class that 
// implements the IDisposable interface and the IDisposable.Dispose
// method with finalization to clean up unmanaged resources. 
//
public ref class MyResource: public IDisposable
{
private:

   // Pointer to an external unmanaged resource.
   IntPtr handle;

   // A managed resource this class uses.
   Component^ component;

   // Track whether Dispose has been called.
   bool disposed;

public:
   // The class constructor.
   MyResource( IntPtr handle, Component^ component )
   {
      this->handle = handle;
      this->component = component;
      disposed = false;
   }

   // This method is called if the user explicitly disposes of the
   // object (by calling the Dispose method in other managed languages, 
   // or the destructor in C++). The compiler emits as a call to 
   // GC::SuppressFinalize( this ) for you, so there is no need to 
   // call it here.
   ~MyResource() 
   {
      // Dispose of managed resources.
      component->~Component();

      // Call C++ finalizer to clean up unmanaged resources.
      this->!MyResource();

      // Mark the class as disposed. This flag allows you to throw an
      // exception if a disposed object is accessed.
      disposed = true;
   }

   // Use interop to call the method necessary to clean up the 
   // unmanaged resource.
   //
   [System::Runtime::InteropServices::DllImport("Kernel32")]
   static Boolean CloseHandle( IntPtr handle );

   // The C++ finalizer destructor ensures that unmanaged resources get
   // released if the user releases the object without explicitly 
   // disposing of it.
   //
   !MyResource()
   {      
      // Call the appropriate methods to clean up unmanaged 
      // resources here. If disposing is false when Dispose(bool,
      // disposing) is called, only the following code is executed.
      CloseHandle( handle );
      handle = IntPtr::Zero;
   }

};

void main()
{
   // Insert code here to create and use the MyResource object.
   MyResource^ mr = gcnew MyResource((IntPtr) 42, (Component^) gcnew Button());
   mr->~MyResource();
}
using System;
using System.ComponentModel;

// The following example demonstrates how to create
// a resource class that implements the IDisposable interface
// and the IDisposable.Dispose method.

public class DisposeExample
{
    // A base class that implements IDisposable.
    // By implementing IDisposable, you are announcing that
    // instances of this type allocate scarce resources.
    public class MyResource: IDisposable
    {
        // Pointer to an external unmanaged resource.
        private IntPtr handle;
        // Other managed resource this class uses.
        private Component component = new Component();
        // Track whether Dispose has been called.
        private bool disposed = false;

        // The class constructor.
        public MyResource(IntPtr handle)
        {
            this.handle = handle;
        }

        // Implement IDisposable.
        // Do not make this method virtual.
        // A derived class should not be able to override this method.
        public void Dispose()
        {
            Dispose(true);
            // This object will be cleaned up by the Dispose method.
            // Therefore, you should call GC.SupressFinalize to
            // take this object off the finalization queue
            // and prevent finalization code for this object
            // from executing a second time.
            GC.SuppressFinalize(this);
        }

        // Dispose(bool disposing) executes in two distinct scenarios.
        // If disposing equals true, the method has been called directly
        // or indirectly by a user's code. Managed and unmanaged resources
        // can be disposed.
        // If disposing equals false, the method has been called by the
        // runtime from inside the finalizer and you should not reference
        // other objects. Only unmanaged resources can be disposed.
        protected virtual void Dispose(bool disposing)
        {
            // Check to see if Dispose has already been called.
            if(!this.disposed)
            {
                // If disposing equals true, dispose all managed
                // and unmanaged resources.
                if(disposing)
                {
                    // Dispose managed resources.
                    component.Dispose();
                }

                // Call the appropriate methods to clean up
                // unmanaged resources here.
                // If disposing is false,
                // only the following code is executed.
                CloseHandle(handle);
                handle = IntPtr.Zero;

                // Note disposing has been done.
                disposed = true;
            }
        }

        // Use interop to call the method necessary
        // to clean up the unmanaged resource.
        [System.Runtime.InteropServices.DllImport("Kernel32")]
        private extern static Boolean CloseHandle(IntPtr handle);

        // Use C# destructor syntax for finalization code.
        // This destructor will run only if the Dispose method
        // does not get called.
        // It gives your base class the opportunity to finalize.
        // Do not provide destructors in types derived from this class.
        ~MyResource()
        {
            // Do not re-create Dispose clean-up code here.
            // Calling Dispose(false) is optimal in terms of
            // readability and maintainability.
            Dispose(false);
        }
    }
    public static void Main()
    {
        // Insert code here to create
        // and use the MyResource object.
    }
}
Imports System.ComponentModel

' The following example demonstrates how to create
' a resource class that implements the IDisposable interface
' and the IDisposable.Dispose method.
Public Class DisposeExample

   ' A class that implements IDisposable.
   ' By implementing IDisposable, you are announcing that 
   ' instances of this type allocate scarce resources.
   Public Class MyResource
      Implements IDisposable
      ' Pointer to an external unmanaged resource.
      Private handle As IntPtr
      ' Other managed resource this class uses.
      Private component As component
      ' Track whether Dispose has been called.
      Private disposed As Boolean = False

      ' The class constructor.
      Public Sub New(ByVal handle As IntPtr)
         Me.handle = handle
      End Sub

      ' Implement IDisposable.
      ' Do not make this method virtual.
      ' A derived class should not be able to override this method.
      Public Overloads Sub Dispose() Implements IDisposable.Dispose
         Dispose(True)
         ' This object will be cleaned up by the Dispose method.
         ' Therefore, you should call GC.SupressFinalize to
         ' take this object off the finalization queue 
         ' and prevent finalization code for this object
         ' from executing a second time.
         GC.SuppressFinalize(Me)
      End Sub

      ' Dispose(bool disposing) executes in two distinct scenarios.
      ' If disposing equals true, the method has been called directly
      ' or indirectly by a user's code. Managed and unmanaged resources
      ' can be disposed.
      ' If disposing equals false, the method has been called by the 
      ' runtime from inside the finalizer and you should not reference 
      ' other objects. Only unmanaged resources can be disposed.
      Protected Overridable Overloads Sub Dispose(ByVal disposing As Boolean)
         ' Check to see if Dispose has already been called.
         If Not Me.disposed Then
            ' If disposing equals true, dispose all managed 
            ' and unmanaged resources.
            If disposing Then
               ' Dispose managed resources.
               component.Dispose()
            End If

            ' Call the appropriate methods to clean up 
            ' unmanaged resources here.
            ' If disposing is false, 
            ' only the following code is executed.
            CloseHandle(handle)
            handle = IntPtr.Zero

            ' Note disposing has been done.
            disposed = True

         End If
      End Sub

      ' Use interop to call the method necessary  
      ' to clean up the unmanaged resource.
      <System.Runtime.InteropServices.DllImport("Kernel32")> _
      Private Shared Function CloseHandle(ByVal handle As IntPtr) As [Boolean]
      End Function

      ' This finalizer will run only if the Dispose method 
      ' does not get called.
      ' It gives your base class the opportunity to finalize.
      ' Do not provide finalize methods in types derived from this class.
      Protected Overrides Sub Finalize()
         ' Do not re-create Dispose clean-up code here.
         ' Calling Dispose(false) is optimal in terms of
         ' readability and maintainability.
         Dispose(False)
         MyBase.Finalize()
      End Sub
   End Class

   Public Shared Sub Main()
      ' Insert code here to create
      ' and use the MyResource object.
   End Sub

End Class

Açıklamalar

Bu arabirimi uygulayan bir sınıf örneği tarafından tutulan dosyalar, akışlar ve tutamaçlar gibi yönetilmeyen kaynakları kapatmak veya serbest bırakmak için bu yöntemi kullanın.Use this method to close or release unmanaged resources such as files, streams, and handles held by an instance of the class that implements this interface. Kural gereği, bu yöntem bir nesne tarafından tutulan kaynakları boşaltma veya bir nesneyi yeniden kullanım için hazırlama ile ilişkili tüm görevler için kullanılır.By convention, this method is used for all tasks associated with freeing resources held by an object, or preparing an object for reuse.

Uyarı

IDisposable arabirimini uygulayan bir sınıf kullanıyorsanız, sınıfını kullanmayı bitirdiğinizde Dispose uygulamasını çağırmanız gerekir.If you are using a class that implements the IDisposable interface, you should call its Dispose implementation when you are finished using the class. Daha fazla bilgi için, IDisposable konusunun "IDisposable uygulayan bir nesne kullanma" bölümüne bakın.For more information, see the "Using an object that implements IDisposable" section in the IDisposable topic.

Bu yöntemi uygularken, tüm tutulan kaynakların, çağrıyı kapsama hiyerarşisi aracılığıyla yayarak serbest olduğundan emin olun.When implementing this method, ensure that all held resources are freed by propagating the call through the containment hierarchy. Örneğin, bir nesne B nesnesini ayırır ve nesne B bir nesne C ayırırsa, bir Dispose uygulamasının B üzerinde Dispose çağırması gerekir ve bu da C üzerinde çağrı Dispose ' de kullanılmalıdır.For example, if an object A allocates an object B, and object B allocates an object C, then A's Dispose implementation must call Dispose on B, which must in turn call Dispose on C.

Önemli

C++ Derleyici kaynakların belirleyici olarak elden çıkarılmasını destekler ve Dispose yönteminin doğrudan uygulanmasına izin vermez.The C++ compiler supports deterministic disposal of resources and does not allow direct implementation of the Dispose method.

Temel sınıf IDisposableuygularsa, bir nesne ayrıca temel sınıfının Dispose yöntemini çağırmalıdır.An object must also call the Dispose method of its base class if the base class implements IDisposable. Temel sınıf ve alt sınıfları üzerinde IDisposable uygulama hakkında daha fazla bilgi için, IDisposable konusunun "IDisposable ve devralma hiyerarşisi" bölümüne bakın.For more information about implementing IDisposable on a base class and its subclasses, see the "IDisposable and the inheritance hierarchy" section in the IDisposable topic.

Bir nesnenin Dispose yöntemi birden çok kez çağrılırsa, nesne birinciden sonra tüm çağrıları yoksaymalıdır.If an object's Dispose method is called more than once, the object must ignore all calls after the first one. Dispose yöntemi birden çok kez çağrılırsa nesne bir özel durum oluşturmamalıdır.The object must not throw an exception if its Dispose method is called multiple times. Dispose dışındaki örnek yöntemleri, kaynaklar zaten elden çıkarıldığı zaman bir ObjectDisposedException oluşturabilir.Instance methods other than Dispose can throw an ObjectDisposedException when resources are already disposed.

Kullanıcılar, ayrılmış bir durumu, serbest bırakılmış duruma göre göstermek için belirli bir kuralı kullanmak üzere bir kaynak türü bekleyebilir.Users might expect a resource type to use a particular convention to denote an allocated state versus a freed state. Buna bir örnek, genellikle açık veya kapalı olarak düşündük akış sınıflarıdır.An example of this is stream classes, which are traditionally thought of as open or closed. Böyle bir kurala sahip bir sınıfın uygulayıcısı, Dispose yöntemini çağıran Closegibi özelleştirilmiş bir ada sahip ortak bir yöntem uygulamayı tercih edebilir.The implementer of a class that has such a convention might choose to implement a public method with a customized name, such as Close, that calls the Dispose method.

Dispose yönteminin açık olarak çağrılması gerektiğinden, yönetilmeyen kaynakların yayınlanmayacak her zaman bir tehlike vardır çünkü bir nesne tüketicisi Dispose metodunu çağıramaz.Because the Dispose method must be called explicitly, there is always a danger that the unmanaged resources will not be released, because the consumer of an object fails to call its Dispose method. Bunu önlemenin iki yolu vardır:There are two ways to avoid this:

StreamWritergibi yönetilmeyen kaynaklara erişen bir nesne kullandığınızda, örneği bir using ifadesiyle oluşturmak iyi bir uygulamadır.When you use an object that accesses unmanaged resources, such as a StreamWriter, a good practice is to create the instance with a using statement. using ifade, akışı otomatik olarak kapatır ve onu kullanan kod tamamlandığında nesnenin Dispose çağırır.The using statement automatically closes the stream and calls Dispose on the object when the code that is using it has completed. Bir örnek için StreamWriter sınıfına bakın.For an example, see the StreamWriter class.

Şunlara uygulanır

Ayrıca bkz.