This documentation is archived and is not being maintained.

InkOverlay.MouseDown Event

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

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

public event InkCollectorMouseDownEventHandler MouseDown

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.


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.


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

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 void mInkObject_MouseDown(object sender, CancelMouseEventArgs e)
    if (InkOverlayEditingMode.Select == mInkObject.EditingMode)
        switch (mInkObject.HitTestSelection(e.X, e.Y))
            case SelectionHitResult.North:
            case SelectionHitResult.East:
            case SelectionHitResult.South:
            case SelectionHitResult.West:

private void ChangeSelectionColor(Color color)
    DrawingAttributes DA = mInkObject.DefaultDrawingAttributes.Clone();
    DA.Color = color;
    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


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.

.NET Framework

Supported in: 3.0