ManipulationStartingEventHandler Delegate

Definition

Namespace:

Windows.UI.Xaml.Input

Represents the method that will handle the ManipulationStarting event.

public delegate void ManipulationStartingEventHandler(Platform::Object ^ sender, ManipulationStartingRoutedEventArgs ^ e);

/// [Windows.Foundation.Metadata.ContractVersion(Windows.Foundation.UniversalApiContract, 65536)]
/// [Windows.Foundation.Metadata.Guid(282112078, 49124, 17099, 130, 60, 63, 236, 216, 119, 14, 248)]
class ManipulationStartingEventHandler : MulticastDelegate

[Windows.Foundation.Metadata.ContractVersion(typeof(Windows.Foundation.UniversalApiContract), 65536)]
[Windows.Foundation.Metadata.Guid(282112078, 49124, 17099, 130, 60, 63, 236, 216, 119, 14, 248)]
public delegate void ManipulationStartingEventHandler(object sender, ManipulationStartingRoutedEventArgs e);

Public Delegate Sub ManipulationStartingEventHandler(sender As Object, e As ManipulationStartingRoutedEventArgs)

Parameters

sender

Object

Platform::Object

IInspectable

The object where the event handler is attached.

e

ManipulationStartingRoutedEventArgs

Event data for the event.

Attributes

ContractVersionAttribute GuidAttribute

Windows requirements

Device family	Windows 10 (introduced in 10.0.10240.0)
API contract	Windows.Foundation.UniversalApiContract (introduced in v1.0)

Examples

The following code example shows scenario 4 from the Input sample. This code shows some usage patterns for direct manipulation using the ManipulationStarting, ManipulationStarted, ManipulationDelta, ManipulationInertiaStarting, and ManipulationCompleted events.

private TransformGroup _transformGroup;
private MatrixTransform _previousTransform;
private CompositeTransform _compositeTransform;
private bool forceManipulationsToEnd;

public Scenario4()
{
    this.InitializeComponent();
    forceManipulationsToEnd = false;
    ManipulateMe.ManipulationStarting += 
        new ManipulationStartingEventHandler(
            ManipulateMe_ManipulationStarting);
    ManipulateMe.ManipulationStarted += 
        new ManipulationStartedEventHandler(
            ManipulateMe_ManipulationStarted);
    ManipulateMe.ManipulationDelta += 
        new ManipulationDeltaEventHandler(
            ManipulateMe_ManipulationDelta);
    ManipulateMe.ManipulationCompleted += 
        new ManipulationCompletedEventHandler(
            ManipulateMe_ManipulationCompleted);
    ManipulateMe.ManipulationInertiaStarting += 
        new ManipulationInertiaStartingEventHandler(
            ManipulateMe_ManipulationInertiaStarting);
    InitManipulationTransforms();
}

private void InitManipulationTransforms()
{
    _transformGroup = new TransformGroup();
    _compositeTransform = new CompositeTransform();
    _previousTransform = new MatrixTransform() { 
        Matrix = Matrix.Identity };

    _transformGroup.Children.Add(_previousTransform);
    _transformGroup.Children.Add(_compositeTransform);

    ManipulateMe.RenderTransform = _transformGroup;
}

private void ManipulateMe_ManipulationStarting(object sender, 
    ManipulationStartingRoutedEventArgs e)
{
    forceManipulationsToEnd = false;
    e.Handled = true;
}

private void ManipulateMe_ManipulationStarted(
    object sender, ManipulationStartedRoutedEventArgs e)
{
    e.Handled = true;
}

private void ManipulateMe_ManipulationInertiaStarting(
    object sender, ManipulationInertiaStartingRoutedEventArgs e)
{
    e.Handled = true;
}

private void ManipulateMe_ManipulationDelta(
    object sender, ManipulationDeltaRoutedEventArgs e)
{
    if (forceManipulationsToEnd)
    {
        e.Complete();
        return;
    }

    _previousTransform.Matrix = _transformGroup.Value;

    Point center = _previousTransform.TransformPoint(
        new Point(e.Position.X, e.Position.Y));
    _compositeTransform.CenterX = center.X;
    _compositeTransform.CenterY = center.Y;

    _compositeTransform.Rotation = (e.Delta.Rotation * 180) / Math.PI;
    _compositeTransform.ScaleX = 
        _compositeTransform.ScaleY = e.Delta.Scale;
    _compositeTransform.TranslateX = e.Delta.Translation.X;
    _compositeTransform.TranslateY = e.Delta.Translation.Y;

    e.Handled = true;
}

private void ManipulateMe_ManipulationCompleted(object sender, 
    ManipulationCompletedRoutedEventArgs e)
{
    e.Handled = true;
}

private void Scenario4Reset(object sender, RoutedEventArgs e)
{
    Scenario4Reset();
}

void Scenario4Reset()
{
    forceManipulationsToEnd = true;
    ManipulateMe.RenderTransform = null;
    InitManipulationTransforms();
}

Private _transformGroup As TransformGroup
Private _previousTransform As MatrixTransform
Private _compositeTransform As CompositeTransform
Private forceManipulationsToEnd As Boolean

Public Sub New()
    Me.InitializeComponent()
    forceManipulationsToEnd = False
    AddHandler ManipulateMe.ManipulationStarting, AddressOf ManipulateMe_ManipulationStarting
    AddHandler ManipulateMe.ManipulationStarted, AddressOf ManipulateMe_ManipulationStarted
    AddHandler ManipulateMe.ManipulationDelta, AddressOf ManipulateMe_ManipulationDelta
    AddHandler ManipulateMe.ManipulationCompleted, AddressOf ManipulateMe_ManipulationCompleted
    InitManipulationTransforms()
End Sub

''' <summary>
''' Invoked when this page is about to be displayed in a Frame.
''' </summary>
''' <param name="e">Event data that describes how this page was reached.  The Parameter
''' property is typically used to configure the page.</param>
Protected Overrides Sub OnNavigatedTo(e As NavigationEventArgs)
End Sub

Private Sub InitManipulationTransforms()
    _transformGroup = New TransformGroup()
    _compositeTransform = New CompositeTransform()
    _previousTransform = New MatrixTransform() With { _
        .Matrix = Matrix.Identity _
    }

    _transformGroup.Children.Add(_previousTransform)
    _transformGroup.Children.Add(_compositeTransform)

    ManipulateMe.RenderTransform = _transformGroup
End Sub

Private Sub ManipulateMe_ManipulationStarting(sender As Object, e As ManipulationStartingRoutedEventArgs)
    forceManipulationsToEnd = False
    e.Handled = True
End Sub

Private Sub ManipulateMe_ManipulationStarted(sender As Object, e As ManipulationStartedRoutedEventArgs)
    e.Handled = True
End Sub

Private Sub ManipulateMe_ManipulationDelta(sender As Object, e As ManipulationDeltaRoutedEventArgs)
    If forceManipulationsToEnd Then
        e.Complete()
        Exit Sub
    End If

    _previousTransform.Matrix = _transformGroup.Value

    Dim center As Point = _previousTransform.TransformPoint(New Point(e.Position.X, e.Position.Y))
    _compositeTransform.CenterX = center.X
    _compositeTransform.CenterY = center.Y

    _compositeTransform.Rotation = (e.Delta.Rotation * 180) / Math.PI
    _compositeTransform.ScaleX = InlineAssignHelper(_compositeTransform.ScaleY, e.Delta.Scale)
    _compositeTransform.TranslateX = e.Delta.Translation.X
    _compositeTransform.TranslateY = e.Delta.Translation.Y

    e.Handled = True
End Sub

Private Sub ManipulateMe_ManipulationCompleted(sender As Object, e As ManipulationCompletedRoutedEventArgs)
    e.Handled = True
End Sub

Private Sub Scenario4ResetMethod(sender As Object, e As RoutedEventArgs)
    Reset()
End Sub

Private Sub Reset()
    forceManipulationsToEnd = True
    ManipulateMe.RenderTransform = Nothing
    InitManipulationTransforms()
End Sub
Private Shared Function InlineAssignHelper(Of T)(ByRef target As T, value As T) As T
    target = value
    Return value
End Function