GC.SuppressFinalize-Methode
Fordert das System auf, den Finalizer für das angegebenen Objekt nicht aufzurufen.
Namespace: System
Assembly: mscorlib (in mscorlib.dll)
Syntax
'Declaration
Public Shared Sub SuppressFinalize ( _
obj As Object _
)
'Usage
Dim obj As Object
GC.SuppressFinalize(obj)
public static void SuppressFinalize (
Object obj
)
public:
static void SuppressFinalize (
Object^ obj
)
public static void SuppressFinalize (
Object obj
)
public static function SuppressFinalize (
obj : Object
)
Parameter
- obj
Das Objekt, für das kein Finalizer aufgerufen werden muss.
Ausnahmen
| Ausnahmetyp | Bedingung |
|---|---|
obj ist NULL (Nothing in Visual Basic). |
Hinweise
Die Methode legt im Objektheader ein Bit fest, das vom System überprüft wird, wenn der Finalizer aufgerufen wird. Der obj-Parameter muss der Aufrufer dieser Methode sein.
Objekte, die die IDisposable-Schnittstelle implementieren, können diese Methode aus der IDisposable.Dispose-Methode heraus aufrufen, um zu verhindern, dass der Garbage Collector für ein Objekt unnötig Object.Finalize aufruft.
Beispiel
Imports System
Imports System.ComponentModel
' The following example demonstrates how to use the
' GC.SuppressFinalize method in a resource class to prevent
' the clean-up code for the object from being called twice.
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 initializes the handle and component.
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.
Private 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
End If
disposed = True
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 a MyResource object.
End Sub
End Class
using System;
using System.ComponentModel;
// The following example demonstrates how to use the
// GC.SuppressFinalize method in a resource class to prevent
// the clean-up code for the object from being called twice.
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: 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.
private 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;
}
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 a MyResource object.
}
}
#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 use the
// GC::SuppressFinalize method to prevent finalization of an
// object that has been disposed. For C++, the call to
// GC::SuppressFinalize is not explicit; it is emitted by the
// compiler, in the Dispose() method. The comments in this code
// example explain where that call occurs and its part in the
// overall Dispose/Finalize pattern.
//
// The code example demonstrates how to create a class that
// implements the IDisposable interface and the IDisposable.Dispose
// method. By implementing IDisposable, you are announcing that
// instances of this type allocate scarce resources, which can be
// released by calling Dispose() when the programmer is finished
// with the object or which will be released when the finalizer
// is executed.
//
// Note that for This code example
//
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;
}
// In managed code, the destructor contains code to clean up managed
// resources. This method is called by Dispose(bool disposing),
// which the C++ compiler emits for you when you implement the
// destructor; it is only called if disposing == true -- that is,
// if the user has called Dispose(). (In C++, the user calls
// ~MyResource(), which the compiler emits as a call to Dispose().)
// The emitted Dispose() method calls GC::SuppressFinalize( this )
// for you, so there is no need to call it here.
~MyResource()
{
// Dispose of managed resources.
component->~Component();
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 );
// Note: The Dispose(bool disposing) method emitted by the
// compiler executes in two distinct scenarios. If disposing ==
// true, the method has been called directly or indirectly by a
// user's code. Managed and unmanaged resources can be disposed,
// so both ~MyResource() and !MyResource() are called.
//
// 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, so
// only !MyResource() is called.
// This destructor runs when the Dispose method gets called
// explicitly, and also when (and if) the Finalizer is run.
!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();
}
import System.* ;
import System.ComponentModel.* ;
// The following example demonstrates how to use the
// GC.SuppressFinalize method in a resource class to prevent
// the clean-up code for the object from being called twice.
public class DisposeExample
{
// A class that implements IDisposable.
// By implementing IDisposable, you are announcing that
// instances of this type allocate scarce resources.
public static class MyResource implements 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 boolean disposed = false;
// The class constructor.
public MyResource(IntPtr handle)
{
this.handle = handle;
} //MyResource
// 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
// 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.
private void Dispose(boolean 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;
}
disposed = true;
} //Dispose
// Use interop to call the method necessary to clean up the unmanaged
// resource.
/** @attribute System.Runtime.InteropServices.DllImport("Kernel32")
*/
private static native Boolean CloseHandle(IntPtr handle);
// Use VJ# 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.
public void finalize()
{
// Do not re-create Dispose clean-up code here.
// Calling Dispose(false) is optimal in terms of
// readability and maintainability.
Dispose(false);
try {
super.finalize();
}
catch (System.Exception e) {
}
} //finalize
} //MyResource
public static void main(String[] args)
{
// Insert code here to create
// and use a MyResource object.
} //main
} //DisposeExample
Plattformen
Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile für Pocket PC, Windows Mobile für Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition
.NET Framework unterstützt nicht alle Versionen sämtlicher Plattformen. Eine Liste der unterstützten Versionen finden Sie unter Systemanforderungen.
Versionsinformationen
.NET Framework
Unterstützt in: 2.0, 1.1, 1.0
.NET Compact Framework
Unterstützt in: 2.0, 1.0