Icon.FromHandle(IntPtr) Método

Definição

Namespace:

System.Drawing

Assembly:

System.Drawing.Common.dll

Pacote:

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

Origem:

Icon.cs

Cria uma Icon GDI+ do identificador do Windows especificado para um ícone (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

Parâmetros

handle

IntPtr

nativeint

Um identificador do Windows para um ícone.

Retornos

Icon

O Icon que esse método cria.

Exemplos

O exemplo de código a seguir foi projetado para uso com o Windows Forms e requer PaintEventArgse, que é um parâmetro do manipulador de eventos Paint. O código executa as seguintes ações:

• Cria um Bitmap.

• Desenha esse objeto para a tela.

• Obtém um identificador de ícone para o Bitmap.

• Define o atributo Form.Icon do formulário como um ícone criado a partir do identificador.

• Chama a função de API do Windows DestroyIcon para liberar recursos.

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

Comentários

Ao usar esse método, você deve descartar o ícone original usando o método DestroyIcon na API do Windows para garantir que os recursos sejam liberados.