Graphics.FromHwnd(IntPtr) Graphics.FromHwnd(IntPtr) Graphics.FromHwnd(IntPtr) Graphics.FromHwnd(IntPtr) Method

Definizione

Crea un nuovo oggetto Graphics dall'handle specificato per una finestra.Creates a new Graphics from the specified handle to a window.

public:
 static System::Drawing::Graphics ^ FromHwnd(IntPtr hwnd);
public static System.Drawing.Graphics FromHwnd (IntPtr hwnd);
static member FromHwnd : nativeint -> System.Drawing.Graphics
Public Shared Function FromHwnd (hwnd As IntPtr) As Graphics

Parametri

hwnd
IntPtr IntPtr IntPtr IntPtr

Handle per una finestra.Handle to a window.

Restituisce

Questo metodo consente di restituire un nuovo oggetto Graphics per l'handle di finestra specificato.This method returns a new Graphics for the specified window handle.

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 thisForm Form eventi e, per l'esempio.The following code example is designed for use with Windows Forms, and it requires PaintEventArgse, which is a parameter of the Paint event handler, as well as thisForm, the Form for the example. Nel codice vengono eseguite le seguenti azioni:The code performs the following actions:

  • Crea una nuova variabile hwnd puntatore interna e la imposta sull'handle del form dell'esempio.Creates a new internal pointer variable hwnd and sets it to the handle of the example's form.

  • Crea un nuovo Graphics oggetto dall'handle.Creates a new Graphics from the handle.

  • Disegna un rettangolo per il nuovo Graphics oggetto utilizzando una penna rossa.Draws a rectangle to the new Graphics using a red pen.

  • Elimina la nuova Graphics.Disposes the new Graphics.

public:
   void FromHwndHwnd( PaintEventArgs^ /*e*/ )
   {
      // Get handle to form.
      IntPtr hwnd = this->Handle;

      // Create new graphics object using handle to window.
      Graphics^ newGraphics = Graphics::FromHwnd( hwnd );

      // Draw rectangle to screen.
      newGraphics->DrawRectangle( gcnew Pen( Color::Red,3.0f ), 0, 0, 200, 100 );

      // Dispose of new graphics.
      delete newGraphics;
   }
private void FromHwndHwnd(PaintEventArgs e)
{

    // Get handle to form.
    IntPtr hwnd = this.Handle;

    // Create new graphics object using handle to window.
    Graphics newGraphics = Graphics.FromHwnd(hwnd);

    // Draw rectangle to screen.
    newGraphics.DrawRectangle(new Pen(Color.Red, 3), 0, 0, 200, 100);

    // Dispose of new graphics.
    newGraphics.Dispose();
}
Private Sub FromHwndHwnd(ByVal e As PaintEventArgs)

    ' Get handle to form.
    Dim hwnd As IntPtr = Me.Handle


    ' Create new graphics object using handle to window.
    Dim newGraphics As Graphics = Graphics.FromHwnd(hwnd)

    ' Draw rectangle to screen.
    newGraphics.DrawRectangle(New Pen(Color.Red, 3), 0, 0, 200, 100)

    ' Dispose of new graphics.
    newGraphics.Dispose()
End Sub

Commenti

È sempre necessario chiamare il Dispose metodo per rilasciare le Graphics risorse FromHwnd correlate e create dal metodo.You should always call the Dispose method to release the Graphics and related resources created by the FromHwnd method.

Sicurezza

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

Si applica a