InkOverlay.MouseDown - событие

Статья
11/04/2008

Обновлен: Ноябрь 2007

Occurs when the mouse pointer is over the InkOverlay object and the user presses a mouse button.

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

Синтаксис

'Декларация
Public Event MouseDown As InkCollectorMouseDownEventHandler
'Применение
Dim instance As InkOverlay
Dim handler As InkCollectorMouseDownEventHandler

AddHandler instance.MouseDown, handler

public event InkCollectorMouseDownEventHandler MouseDown

public:
 event InkCollectorMouseDownEventHandler^ MouseDown {
    void add (InkCollectorMouseDownEventHandler^ value);
    void remove (InkCollectorMouseDownEventHandler^ value);
}

/** @event */
public void add_MouseDown (InkCollectorMouseDownEventHandler value)
/** @event */
public void remove_MouseDown (InkCollectorMouseDownEventHandler value)

JScript не поддерживает события.

Заметки

The event handler receives an argument of type CancelMouseEventArgs containing data about this event.

When you create a InkCollectorMouseDownEventHandler 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. For performance reasons, the default event interest is off but is turned on automatically if you add an event handler.

To improve real-time ink performance, hide the mouse cursor while inking. To do so, hide the mouse cursor in the MouseDown event handler, and show the mouse cursor in the MouseUp event handler.

Примечание.
The CancelMouseEventArgs object's X and Y properties are in pixels and not the HIMETRIC units that are associated with the ink space. This is because this event replaces the related mouse event of an application that is not pen-aware, and that type of application is depicted in pixels.

Примечание.
Some controls rely on a specific relationship between MouseDown, MouseMove, and MouseUp events. Canceling some of these events may have unanticipated results.

Примеры

In this example, when the MouseDown event fires, a check is made to see if EditingMode is set to Select. If so, the HitTestSelection method is called to determine which part of the selection (if any) has been hit. If the hit occurs on any of the four main compass directions, as specified by the SelectionHitResult enumeration, the stroke objects that are selected are changed to a different color.

Private Sub mInkObject_MouseDown(ByVal sender As Object, ByVal e As CancelMouseEventArgs)

    If InkOverlayEditingMode.Select = mInkObject.EditingMode Then
        Select Case mInkObject.HitTestSelection(e.X, e.Y)
            Case SelectionHitResult.North
                ChangeSelectionColor(Color.Green)
            Case SelectionHitResult.East
                ChangeSelectionColor(Color.Red)
            Case SelectionHitResult.South
                ChangeSelectionColor(Color.Purple)
            Case SelectionHitResult.West
                ChangeSelectionColor(Color.Blue)
        End Select
    End If
End Sub

Private Sub ChangeSelectionColor(ByVal color As Color)
    Dim DA As DrawingAttributes = mInkObject.DefaultDrawingAttributes.Clone()
    DA.Color = color
    mInkObject.Selection.ModifyDrawingAttributes(DA)
    Using G As Graphics = CreateGraphics()
        ' Get the bounding box of the selection. The default is
        ' to include the width of the strokes in the calculation.
        ' The returned rectangle is measured in ink units.
        Dim rInkUnits As Rectangle = mInkObject.Selection.GetBoundingBox()

        ' In selection mode, the selected strokes are drawn inflated
        ' GetBoundingBox() does not take this into account
        ' Rectangle rInkUnits is inflated to compensate
        rInkUnits.Inflate(53, 53)

        Dim topLeft As Point = rInkUnits.Location
        Dim bottomRight As Point = rInkUnits.Location + rInkUnits.Size

        ' get a Renderer object to make the conversion
        Dim R As Renderer = New Renderer()

        ' convert the points to pixels
        R.InkSpaceToPixel(G, topLeft)
        R.InkSpaceToPixel(G, bottomRight)

        ' create a rectangle that is in pixels
        Dim rPixelUnits As Rectangle = _
            New Rectangle(topLeft, New Size(bottomRight.X - topLeft.X, bottomRight.Y - topLeft.Y))

        ' Redraw the strokes
        mInkObject.Draw(rPixelUnits)

    End Using
End Sub

private void mInkObject_MouseDown(object sender, CancelMouseEventArgs e)
{
    if (InkOverlayEditingMode.Select == mInkObject.EditingMode)
    {
        switch (mInkObject.HitTestSelection(e.X, e.Y))
        {
            case SelectionHitResult.North:
                ChangeSelectionColor(Color.Green);
                break;
            case SelectionHitResult.East:
                ChangeSelectionColor(Color.Red);
                break;
            case SelectionHitResult.South:
                ChangeSelectionColor(Color.Purple);
                break;
            case SelectionHitResult.West:
                ChangeSelectionColor(Color.Blue);
                break;
        }
    }
}

private void ChangeSelectionColor(Color color)
{
    DrawingAttributes DA = mInkObject.DefaultDrawingAttributes.Clone();
    DA.Color = color;
    mInkObject.Selection.ModifyDrawingAttributes(DA);
    using (Graphics G = CreateGraphics())
    {
        // Get the bounding box of the selection. The default is
        // to include the width of the strokes in the calculation.
        // The returned rectangle is measured in ink units.
        Rectangle rInkUnits = mInkObject.Selection.GetBoundingBox();

        // In selection mode, the selected strokes are drawn inflated
        // GetBoundingBox() does not take this into account
        // Rectangle rInkUnits is inflated to compensate
        rInkUnits.Inflate(53, 53);

        Point topLeft = rInkUnits.Location;
        Point bottomRight = rInkUnits.Location + rInkUnits.Size;

        // get a Renderer object to make the conversion
        Renderer R = new Renderer();

        // convert the points to pixels
        R.InkSpaceToPixel(G, ref topLeft);
        R.InkSpaceToPixel(G, ref bottomRight);

        // create a rectangle that is in pixels
        Rectangle rPixelUnits =
            new Rectangle(topLeft, new Size(bottomRight.X - topLeft.X, bottomRight.Y - topLeft.Y));

        // Redraw the strokes
        mInkObject.Draw(rPixelUnits);

    } 
}

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.