ManipulationDeltaEventArgs.ReportBoundaryFeedback(ManipulationDelta) Método

Definição

Namespace:

System.Windows.Input

Assembly:

PresentationCore.dll

Especifica que a manipulação foi além de determinados limites.

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)

Parâmetros

unusedManipulation

ManipulationDelta

A parte da manipulação que representa ir além do limite.

Exceções

ArgumentNullException

unusedManipulation é null.

Exemplos

O exemplo a seguir mostra um manipulador de eventos para o ManipulationDelta evento que chama o ReportBoundaryFeedback método quando o usuário move o elemento sobre a borda de seu contêiner. Para testar este exemplo, siga as etapas em Passo a passo: Criando seu primeiro aplicativo de toque e substitua o código na etapa 5 por esse 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

Comentários

Use o ReportBoundaryFeedback método para indicar que um elemento foi movido além de um determinado limite. Por exemplo, se um usuário mover um elemento fora dos limites de um Window, você poderá chamar esse método para relatar isso à janela. Quando você chama ReportBoundaryFeedback, o ManipulationBoundaryFeedback evento ocorre. Por padrão, o Window assina o ManipulationBoundaryFeedback evento para fornecer comentários visuais ao usuário que um limite foi atingido. Você pode assinar para ManipulationBoundaryFeedback implementar o comportamento personalizado.