Icon.FromHandle(IntPtr) Metodo

Definizione

Spazio dei nomi:

System.Drawing

Assembly:

System.Drawing.Common.dll

Pacchetto:

System.Drawing.Common v9.0.0-rc.2.24474.1

Origine:

Icon.cs

Crea un Icon GDI+ dall'handle di Windows specificato a un'icona (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

nativeint

Handle di Windows per un'icona.

Restituisce

Icon

Il Icon questo metodo crea.

Esempio

L'esempio di codice seguente è progettato per l'uso con Windows Form e richiede PaintEventArgse, che è un parametro del gestore eventi Paint. Il codice esegue le azioni seguenti:

• Crea un Bitmap.

• Disegna l'oggetto sullo schermo.

• Ottiene un handle icona per il Bitmap.

• Imposta l'attributo Form.Icon del form su un'icona creata dall'handle.

• Chiama la funzione API Windows DestroyIcon per rilasciare le risorse.

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 metodo DestroyIcon nell'API Windows per assicurarsi che le risorse vengano rilasciate.