InkEditStrokeEventHandler Delegate

Article
10/20/2012

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

Namespace: Microsoft.Ink
Assembly: Microsoft.Ink (in Microsoft.Ink.dll)

Syntax

'Declaration
Public Delegate Sub InkEditStrokeEventHandler ( _
    sender As Object, _
    e As InkEditStrokeEventArgs _
)
'Usage
Dim instance As New InkEditStrokeEventHandler(AddressOf HandlerMethod)

public delegate void InkEditStrokeEventHandler(
    Object sender,
    InkEditStrokeEventArgs e
)

public delegate void InkEditStrokeEventHandler(
    Object^ sender, 
    InkEditStrokeEventArgs^ e
)

JScript does not support delegates.

Parameters

sender
Type: System.Object

The source InkEdit control of this event.

e
Type: Microsoft.Ink.InkEditStrokeEventArgs

The InkEditStrokeEventArgs object that contains the event data.

Remarks

When you create an InkEditStrokeEventHandler 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.

Examples

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);
}

Platforms

Windows 7, Windows Vista, Windows Server 2008 R2, Windows Server 2008

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Version Information

.NET Framework

Supported in: 3.0

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