Stroke.OnInvalidated(EventArgs) Method

Reference

Definition

Namespace:: System.Windows.Ink

Assembly:: PresentationCore.dll

Important

Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.

Raises the Invalidated event.

protected:
 virtual void OnInvalidated(EventArgs ^ e);

protected virtual void OnInvalidated (EventArgs e);

abstract member OnInvalidated : EventArgs -> unit
override this.OnInvalidated : EventArgs -> unit

Protected Overridable Sub OnInvalidated (e As EventArgs)

Parameters

e: EventArgs

An EventArgs that contains the event data.

Examples

The following example draws a Stroke either as a solid stroke or as a series of StylusPoint objects, depending on the Mode property. The example calls the OnInvalidated method, which in turn calls the DrawCore where the stroke is drawn.

// Enumerator that specifies the drawing mode of the stroke.
public enum DrawingMode
{
    Solid,
    StyulusPoints
}

' Enumerator that specifies the drawing mode of the stroke.

Public Enum DrawingMode
    Solid
    StyulusPoints
End Enum 'DrawingMode

private DrawingMode strokeMode = DrawingMode.Solid;

// Property that specifies whether to draw a solid stroke or the stylus points
public DrawingMode Mode
{
    get
    {
        return strokeMode;
    }

     set
    {
        if (strokeMode != value)
        {
            strokeMode = value;
            this.OnInvalidated(new EventArgs());
        }
    }
}

protected override void DrawCore(System.Windows.Media.DrawingContext context, DrawingAttributes overrides)
{
    SolidColorBrush strokeBrush = new SolidColorBrush(overrides.Color);

    // If strokeMode it set to Solid, draw the strokes regularly.
    // Otherwise, draw the stylus points.
    if (strokeMode == DrawingMode.Solid)
    {
        Geometry geometry = GetGeometry(overrides);
        context.DrawGeometry(strokeBrush, null, geometry);
    }
    else // strokeMode == DrawingMode.StylusPoints
    {
        StylusPointCollection points;

        // Get the stylus points used to draw the stroke.  The points used depends on
        // the value of FitToCurve.
        if (this.DrawingAttributes.FitToCurve)
        {
            points = this.GetBezierStylusPoints();
        }
        else
        {
            points = this.StylusPoints;
        }

        // Draw a circle at each stylus point.
        foreach (StylusPoint p in points)
        {
            context.DrawEllipse(null, new Pen(strokeBrush, 1), (Point)p, 5, 5);
        }
    }
}

Private strokeMode As DrawingMode = DrawingMode.Solid

' Property that specifies whether to draw a solid stroke or the stylus points
Public Property Mode() As DrawingMode

    Get
        Return strokeMode
    End Get

    Set(ByVal value As DrawingMode)
        If strokeMode <> value Then
            strokeMode = value
            Me.OnInvalidated(New EventArgs())
        End If
    End Set

End Property


Protected Overrides Sub DrawCore(ByVal context As System.Windows.Media.DrawingContext, _
            ByVal overridedAttributes As DrawingAttributes)
    Dim strokeBrush As New SolidColorBrush(overridedAttributes.Color)

    ' If strokeMode it set to Solid, draw the strokes regularly.
    ' Otherwise, draw the stylus points.
    If strokeMode = DrawingMode.Solid Then
        Dim geometry As Geometry = GetGeometry(overridedAttributes)
        context.DrawGeometry(strokeBrush, Nothing, geometry)
        ' strokeMode == DrawingMode.StylusPoints
    Else
        Dim points As StylusPointCollection

        ' Get the stylus points used to draw the stroke.  The points used depends on
        ' the value of FitToCurve.
        If Me.DrawingAttributes.FitToCurve Then
            points = Me.GetBezierStylusPoints()
        Else
            points = Me.StylusPoints
        End If

        ' Draw a circle at each stylus point.
        Dim p As StylusPoint
        For Each p In points
            context.DrawEllipse(Nothing, New Pen(strokeBrush, 1), CType(p, Point), 5, 5)
        Next p
    End If

End Sub

Remarks

If you inherit from the Stroke class and your stroke's appearance is based on a custom state, you must call the OnInvalidated method to raise the Invalidated event. The InkPresenter handles the Invalidated event and calls the DrawCore method.

Applies to

Delen via