InkEditGestureEventHandler - делегат

Статья
11/04/2008

Обновлен: Ноябрь 2007

Represents the method that handles the Gesture event of an InkEdit control.

Пространство имен: Microsoft.Ink
Сборка: Microsoft.Ink (в Microsoft.Ink.dll)

Синтаксис

'Декларация
Public Delegate Sub InkEditGestureEventHandler ( _
    sender As Object, _
    e As InkEditGestureEventArgs _
)
'Применение
Dim instance As New InkEditGestureEventHandler(AddressOf HandlerMethod)

public delegate void InkEditGestureEventHandler(
    Object sender,
    InkEditGestureEventArgs e
)

public delegate void InkEditGestureEventHandler(
    Object^ sender, 
    InkEditGestureEventArgs^ e
)

/** @delegate */
public delegate void InkEditGestureEventHandler(
    Object sender,
    InkEditGestureEventArgs e
)

JScript не поддерживает делегаты.

Параметры

sender
Тип: System.Object
The source InkEdit control of this event.

e
Тип: Microsoft.Ink.InkEditGestureEventArgs
The InkEditGestureEventArgs object that contains the event data.

Заметки

An application gesture is a gesture supported within your application.

For this event to occur, the InkEdit control must have interest in a set of application gestures. To set the InkEdit control's interest in a set of gestures, call the SetGestureStatus method of the InkEdit control.

For a list of specific application gestures, see the ApplicationGesture enumeration type. For more information about application gestures, see Using Gestures and Command Input on the Tablet PC.

When you create an InkEditGestureEventHandler delegate, you identify the method that handles the event. To associate the event with your event handler, add an instance of the delegate to the event. The event handler is called whenever the event occurs, unless you remove the delegate.

In the InkEdit control, a Gesture event is raised only if the gesture is the first stroke since the last call to the Recognize method or the last firing of the recognition timeout.

If the Gesture event is cancelled, the Stroke event is raised for the Stroke objects that raised the Gesture event.

The InkEdit control does not recognize multistroke gestures.

The InkEdit control has default interest in and actions for the following gestures:

Gesture	Action
Down-left,Down-left-long	Enter
Right	Space
Left	Backspace
Up-right,Up-right-long	Tab

To alter the default action for a gesture:

Add event handlers for the Gesture and Stroke events.
In the Gesture event handler, cancel the Gesture event for the gesture, and perform the alternate action for the gesture.
In the InkEditStrokeEventHandler delegate, cancel the Stroke event for the Stroke object that raised the cancelled Gesture event.

Примеры

This example demonstrates how you can subscribe to the Gesture event and the Stroke event to augment the functionality of an ApplicationGesture.

When the Gesture event fires, it examines the gesture and the current state of the InkEdit control. If necessary, the behavior of the gesture is modified and the event is cancelled.

Private Sub mInkEdit_Gesture(ByVal sender As Object, ByVal e As InkEditGestureEventArgs)
    ' There might be more than one gesture passed in InkEditGestureEventArgs
    ' The gestures are arranged in order of confidence from most to least
    ' This event handler is only concerned with the first (most confident) gesture
    ' and only if the gesture is ApplicationGesture.Left with strong confidence
    Dim G As Gesture = e.Gestures(0)
    If (ApplicationGesture.Left = G.Id And RecognitionConfidence.Strong = G.Confidence) Then
        Dim pInkEdit As InkEdit = DirectCast(sender, InkEdit)
        ' by default, ApplicationGesture.Left maps to Backspace
        ' If the insertion point is at the beginning of the text
        ' and there is no text selected, then Backspace does not do anything.
        ' In this case, we will alter the gesture to map to Delete instead
        If (0 = pInkEdit.SelectionStart And 0 = pInkEdit.SelectionLength And pInkEdit.Text.Length > 0) Then
            ' take out the first character of the string
            pInkEdit.Text = pInkEdit.Text.Remove(0, 1)
            ' save the stroke ID in a class level var for use in the Stroke event
            Me.mStrokeID = e.Strokes(0).Id
            ' cancel the gesture so it won't perform the default action
            e.Cancel = True
        End If
    End If
End Sub

private void mInkEdit_Gesture(object sender, InkEditGestureEventArgs e)
{
    // There might be more than one gesture passed in InkEditGestureEventArgs
    // The gestures are arranged in order of confidence from most to least
    // This event handler is only concerned with the first (most confident) gesture
    // and only if the gesture is ApplicationGesture.Left with strong confidence
    Gesture G = e.Gestures[0];
    if (ApplicationGesture.Left == G.Id &&  RecognitionConfidence.Strong == G.Confidence)
    {
        InkEdit pInkEdit = (InkEdit)sender;

        // by default, ApplicationGesture.Left maps to Backspace
        // If the insertion point is at the beginning of the text
        // and there is no text selected, then Backspace does not do anything.
        // In this case, we will alter the gesture to map to Delete instead
        if (0 == pInkEdit.SelectionStart && 0 == pInkEdit.SelectionLength && pInkEdit.Text.Length > 0)
        {
            // take out the first character of the string
            pInkEdit.Text = pInkEdit.Text.Remove(0, 1);
            // save the stroke ID in a class level var for use in the Stroke event
            this.mStrokeID = e.Strokes[0].Id;
            // cancel the gesture so it won't perform the default action
            e.Cancel = true;
        }
    }
}

When the Stroke event fires, the event is cancelled if the stroke is the one that was used to generate the gesture whose behavior was modified in the Gesture event. This prevents the stroke from rendering.

Private Sub mInkEdit_Stroke(ByVal sender As Object, ByVal e As InkEditStrokeEventArgs)
    e.Cancel = (e.Stroke.Id = Me.mStrokeID)
End Sub

private void mInkEdit_Stroke(object sender, InkEditStrokeEventArgs e)
{
    e.Cancel = (e.Stroke.Id == this.mStrokeID);
}

Платформы

Windows Vista

Среды .NET Framework и .NET Compact Framework поддерживают не все версии каждой платформы. Поддерживаемые версии перечислены в разделе Требования к системе для .NET Framework.