Icon.FromHandle(IntPtr) Icon.FromHandle(IntPtr) Icon.FromHandle(IntPtr) Icon.FromHandle(IntPtr) Method

Definizione

Crea un oggetto Icon GDI+ dall'handle Windows specificato per un'icona (HICON).Creates a GDI+ Icon from the specified Windows handle to an icon (HICON).

public:
 static System::Drawing::Icon ^ FromHandle(IntPtr handle);
public static System.Drawing.Icon FromHandle (IntPtr handle);
static member FromHandle : nativeint -> System.Drawing.Icon
Public Shared Function FromHandle (handle As IntPtr) As Icon

Parametri

handle
IntPtr IntPtr IntPtr IntPtr

Handle di Windows per un'icona.A Windows handle to an icon.

Restituisce

Oggetto Icon creato da questo metodo.The Icon this method creates.

Esempi

L'esempio di codice seguente è progettato per l'uso con Windows Forms e richiede PaintEventArgs e, che Paint è un parametro del gestore eventi.The following code example is designed for use with Windows Forms, and it requires PaintEventArgse, which is a parameter of the Paint event handler. Nel codice vengono eseguite le seguenti azioni:The code performs the following actions:

  • Crea un oggetto Bitmap.Creates a Bitmap.

  • Disegna l'oggetto sullo schermo.Draws that object to the screen.

  • Ottiene un handle di icona per Bitmapl'oggetto.Gets an icon handle for the Bitmap.

  • Imposta l' Form.Icon attributo del form su un'icona creata dall'handle.Sets the Form.Icon attribute of the form to an icon created from the handle.

  • Chiama la funzione DestroyIcon API di Windows per rilasciare le risorse.Calls the Windows API function DestroyIcon to release resources.

private:
   [System::Runtime::InteropServices::DllImportAttribute("user32.dll",CharSet=CharSet::Auto)]
   static bool DestroyIcon( IntPtr handle );

private:
   [SecurityPermission(SecurityAction::Demand, Flags=SecurityPermissionFlag::UnmanagedCode)]
   void GetHicon_Example( PaintEventArgs^ e )
   {
      
      // Create a Bitmap object from an image file.
      Bitmap^ myBitmap = gcnew Bitmap( "c:\\FakePhoto.jpg" );
      
      // Draw myBitmap to the screen.
      e->Graphics->DrawImage( myBitmap, 0, 0 );
      
      // Get an Hicon for myBitmap.
      IntPtr Hicon = myBitmap->GetHicon();
      
      // Create a new icon from the handle. 
      System::Drawing::Icon^ newIcon = ::Icon::FromHandle( Hicon );
      
      // Set the form Icon attribute to the new icon.
      this->Icon = newIcon;
      
      // You can now destroy the Icon, since the form creates
      // its own copy of the icon accesible through the Form.Icon property.
      DestroyIcon( newIcon->Handle );
   }

[System.Runtime.InteropServices.DllImport("user32.dll", CharSet = CharSet.Auto)]
extern static bool DestroyIcon(IntPtr handle);

private void GetHicon_Example(PaintEventArgs e)
{

    // Create a Bitmap object from an image file.
    Bitmap myBitmap = new Bitmap(@"c:\FakePhoto.jpg");

    // Draw myBitmap to the screen.
    e.Graphics.DrawImage(myBitmap, 0, 0);

    // Get an Hicon for myBitmap.
    IntPtr Hicon = myBitmap.GetHicon();

    // Create a new icon from the handle. 
    Icon newIcon = Icon.FromHandle(Hicon);

    // Set the form Icon attribute to the new icon.
    this.Icon = newIcon;

    // You can now destroy the icon, since the form creates
    // its own copy of the icon accessible through the Form.Icon property.
    DestroyIcon(newIcon.Handle);

}
<System.Runtime.InteropServices.DllImportAttribute("user32.dll")> _
    Private Shared Function DestroyIcon(ByVal handle _ 
	As IntPtr) As Boolean 
    End Function

   Private Sub GetHicon_Example(ByVal e As PaintEventArgs)

        ' Create a Bitmap object from an image file.
        Dim myBitmap As New Bitmap("c:\FakePhoto.jpg")

        ' Draw myBitmap to the screen.
        e.Graphics.DrawImage(myBitmap, 0, 0)

        ' Get an Hicon for myBitmap.
        Dim HIcon As IntPtr = myBitmap.GetHicon()
	
        ' Create a new icon from the handle.
        Dim newIcon As Icon = System.Drawing.Icon.FromHandle(HIcon)

        ' Set the form Icon attribute to the new icon.
        Me.Icon = newIcon

        ' You can now destroy the icon, since the form creates its 
        ' own copy of the icon accessible through the Form.Icon property.
	DestroyIcon(newIcon.Handle)
    End Sub

Commenti

Quando si usa questo metodo, è necessario eliminare l'icona originale usando il DestroyIcon metodo nell'API Windows per assicurarsi che le risorse vengano rilasciate.When using this method, you must dispose of the original icon by using the DestroyIcon method in the Windows API to ensure that the resources are released.

Sicurezza

SecurityPermission
per l'accesso al codice non gestito.for access to unmanaged code. Enumerazione UnmanagedCodecorrelata.Related enumeration UnmanagedCode.

Si applica a