ManipulationDeltaEventArgs.ReportBoundaryFeedback(ManipulationDelta) Método

Definición

Espacio de nombres:

System.Windows.Input

Ensamblado:

PresentationCore.dll

Especifica que la manipulación ha excedido ciertos límites.

public:
 void ReportBoundaryFeedback(System::Windows::Input::ManipulationDelta ^ unusedManipulation);

public void ReportBoundaryFeedback (System.Windows.Input.ManipulationDelta unusedManipulation);

member this.ReportBoundaryFeedback : System.Windows.Input.ManipulationDelta -> unit

Public Sub ReportBoundaryFeedback (unusedManipulation As ManipulationDelta)

Parámetros

unusedManipulation

ManipulationDelta

La parte de la manipulación que representa la mudanza más allá del límite.

Excepciones

ArgumentNullException

unusedManipulation es null.

Ejemplos

En el ejemplo siguiente se muestra un controlador de eventos para el ManipulationDelta evento que llama al ReportBoundaryFeedback método cuando el usuario mueve el elemento sobre el borde de su contenedor. Para probar este ejemplo, siga los pasos descritos en Tutorial: Crear la primera aplicación táctil y reemplazar el código del paso 5 por este código.

void Window_ManipulationDelta(object sender, ManipulationDeltaEventArgs e)
{

    Rectangle rectToMove = e.OriginalSource as Rectangle;
    Vector overshoot;

    // When the element crosses the boundary of the window, check whether 
    // the manipulation is in inertia.  If it is, complete the manipulation.
    // Otherwise, report the boundary feedback.
    if (CalculateOvershoot(rectToMove, e.ManipulationContainer, out overshoot))
    {
        if (e.IsInertial)
        {
            e.Complete();
            e.Handled = true;
            return;
        }
        else
        {
            //Report that the element hit the boundary
            e.ReportBoundaryFeedback(new ManipulationDelta(overshoot, 0, new Vector(), new Vector()));
        }
    }
  
    // Move the element as usual.

    // Get the Rectangle and its RenderTransform matrix.
    Matrix rectsMatrix = ((MatrixTransform)rectToMove.RenderTransform).Matrix;

    // Rotate the Rectangle.
    rectsMatrix.RotateAt(e.DeltaManipulation.Rotation,
                         e.ManipulationOrigin.X,
                         e.ManipulationOrigin.Y);

    // Resize the Rectangle.  Keep it square 
    // so use only the X value of Scale.
    rectsMatrix.ScaleAt(e.DeltaManipulation.Scale.X,
                        e.DeltaManipulation.Scale.X,
                        e.ManipulationOrigin.X,
                        e.ManipulationOrigin.Y);

    // Move the Rectangle.
    rectsMatrix.Translate(e.DeltaManipulation.Translation.X,
                          e.DeltaManipulation.Translation.Y);

    // Apply the changes to the Rectangle.
    rectToMove.RenderTransform = new MatrixTransform(rectsMatrix);

    e.Handled = true;
}

private bool CalculateOvershoot(UIElement element, IInputElement container, out Vector overshoot)
{
    // Get axis aligned element bounds
    var elementBounds = element.RenderTransform.TransformBounds(
                  VisualTreeHelper.GetDrawing(element).Bounds);

    //double extraX = 0.0, extraY = 0.0;
    overshoot = new Vector();

    FrameworkElement parent = container as FrameworkElement;
    if (parent == null)
    {
        return false;
    }

    // Calculate overshoot.  
    if (elementBounds.Left < 0)
        overshoot.X = elementBounds.Left;
    else if (elementBounds.Right > parent.ActualWidth)
        overshoot.X = elementBounds.Right - parent.ActualWidth;

    if (elementBounds.Top < 0)
        overshoot.Y = elementBounds.Top;
    else if (elementBounds.Bottom > parent.ActualHeight)
        overshoot.Y = elementBounds.Bottom - parent.ActualHeight;

    // Return false if Overshoot is empty; otherwsie, return true.
    return !Vector.Equals(overshoot, new Vector());
}

Private Sub Window_ManipulationDelta(ByVal sender As Object, ByVal e As ManipulationDeltaEventArgs)

    Dim rectToMove As Rectangle = TryCast(e.OriginalSource, Rectangle)
    Dim overshoot As Vector

    ' When the element crosses the boundary of the window, check whether 
    ' the manipulation is in inertia. If it is, complete the manipulation.
    ' Otherwise, report the boundary feedback.
    If CalculateOvershoot(rectToMove, e.ManipulationContainer, overshoot) Then
        If e.IsInertial Then
            e.Complete()
            e.Handled = True
            Exit Sub
        Else
            'Report that the element hit the boundary

            e.ReportBoundaryFeedback(New ManipulationDelta(overshoot, 0, New Vector(), New Vector()))
        End If
    End If

    ' Move the element as usual.

    ' Get the Rectangle and its RenderTransform matrix.
    Dim rectsMatrix As Matrix = DirectCast(rectToMove.RenderTransform, MatrixTransform).Matrix

    ' Rotate the Rectangle.
    rectsMatrix.RotateAt(e.DeltaManipulation.Rotation, e.ManipulationOrigin.X, e.ManipulationOrigin.Y)

    ' Resize the Rectangle. Keep it square 
    ' so use only the X value of Scale.
    rectsMatrix.ScaleAt(e.DeltaManipulation.Scale.X, e.DeltaManipulation.Scale.X, e.ManipulationOrigin.X, e.ManipulationOrigin.Y)

    ' Move the Rectangle.
    rectsMatrix.Translate(e.DeltaManipulation.Translation.X, e.DeltaManipulation.Translation.Y)

    ' Apply the changes to the Rectangle.
    rectToMove.RenderTransform = New MatrixTransform(rectsMatrix)

    e.Handled = True
End Sub

Private Function CalculateOvershoot(ByVal element As UIElement, ByVal container As IInputElement, ByRef overshoot As Vector) As Boolean
    ' Get axis aligned element bounds
    Dim elementBounds = element.RenderTransform.TransformBounds(VisualTreeHelper.GetDrawing(element).Bounds)

    'double extraX = 0.0, extraY = 0.0;
    overshoot = New Vector()

    Dim parent As FrameworkElement = TryCast(container, FrameworkElement)
    If parent Is Nothing Then
        Return False
    End If

    ' Calculate overshoot. 
    If elementBounds.Left < 0 Then
        overshoot.X = elementBounds.Left
    ElseIf elementBounds.Right > parent.ActualWidth Then
        overshoot.X = elementBounds.Right - parent.ActualWidth
    End If

    If elementBounds.Top < 0 Then
        overshoot.Y = elementBounds.Top
    ElseIf elementBounds.Bottom > parent.ActualHeight Then
        overshoot.Y = elementBounds.Bottom - parent.ActualHeight
    End If

    ' Return false if Overshoot is empty; otherwsie, return true.
    Return Not Vector.Equals(overshoot, New Vector())
End Function

Comentarios

Use el ReportBoundaryFeedback método para indicar que un elemento se ha movido más allá de un determinado límite. Por ejemplo, si un usuario mueve un elemento fuera de los límites de un Window, puede llamar a este método para notificarlo a la ventana. Cuando se llama a ReportBoundaryFeedback, se produce el ManipulationBoundaryFeedback evento . De forma predeterminada, se Window suscribe al ManipulationBoundaryFeedback evento para proporcionar comentarios visuales al usuario al que se ha alcanzado un límite. Puede suscribirse a ManipulationBoundaryFeedback para implementar el comportamiento personalizado.