Silverlight : MouseLeftButtonUp is not triggered

Question

I'm new to Silverlight and I'm working on drawing a rectangle on the screen in the run time,

I have a class ( SelectionBox ), and on the main page, I have a canvas, when clicking on that Canvas I have the following function called

private void BeginDrawing(object sender, System.Windows.Input.MouseButtonEventArgs e)
        {
            _initXPos = e.GetPosition(drawingArea).X;
            _initYPos = e.GetPosition(drawingArea).Y;
            _selectionBox = new SelectionBox ();
            drawingArea.Children.Add(_selectionBox);
            _isDrawing = true;
        }

and that Handler has been added through blend Events (MouseLeftButtonDown)

when the mouse is moving, the following method is called, also added through Blend events,

private void UpdateSelectionBox(object sender, System.Windows.Input.MouseEventArgs e)
        {
            if(!_isDrawing &&)
                return;
            double rectWidth, rectHeight, rectXPos, rectYPos;
            if (e.GetPosition(drawingArea).X >= _initXPos)
            {
                rectWidth = e.GetPosition(drawingArea).X - _initXPos;
                rectXPos = _initXPos;
            }
            else
            {
                rectWidth = _initXPos - e.GetPosition(drawingArea).X;
                rectXPos = e.GetPosition(drawingArea).X;
            }

            if (e.GetPosition(drawingArea).Y >= _initYPos)
            {
                rectHeight = e.GetPosition(drawingArea).Y - _initYPos;
                rectYPos = _initYPos;
            }
            else
            {
                rectHeight = _initYPos - e.GetPosition(drawingArea).Y;
                rectYPos = e.GetPosition(drawingArea).Y;
            }

            _selectionBox.Width = Math.Abs(rectWidth - 20);
            _selectionBox.Height = Math.Abs(rectHeight - 20);
            Canvas.SetLeft(_selectionBox, Math.Abs(rectXPos - 20));
            Canvas.SetTop(_selectionBox, Math.Abs(rectYPos - 20));
        }

when the mouseLeftButtonUp is triggered, the following Handler should work,

private void StopDrawingAndSelect(object sender, System.Windows.Input.MouseButtonEventArgs e)
        {
            _isDrawing = false;
            drawingArea.Children.Remove(_selectionBox);
        }

but unfortunately it never triggers, I put a break point and try to debug it but it never reaches,, I'm not sure Why, this is the XAML for the SelectionBox class

<UserControl
    ...

    <Grid x:Name="LayoutRoot">
        <Rectangle Fill="#00F4F4F5" Stroke="Black" StrokeDashArray="1 2"/>
    </Grid>
</UserControl>

And this is the XAML of the MainPage

<UserControl xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:local="clr-namespace:SelectionBoxTraining"
    x:Class="SelectionBoxTraining.MainPage"
    Width="640" Height="480">

    <Grid x:Name="LayoutRoot" Background="White">
        <Canvas Margin="165,0,0,0" x:Name="drawingArea" MouseLeftButtonDown="BeginDrawing" Background="#FF959FD6" MouseMove="UpdateSelectionBox" MouseLeftButtonUp="StopDrawingAndSelect" />

    </Grid>
</UserControl>

Please can anybody help me? I tried a lot of things to do but that didn't work

I hope I find help here,

NOTE: The properties are not included in the XAML code upthere to save space,

Thank You.

Oh,, I forgot to say that If I Apply the StopDrawingAndSelect to the RightMouseButtonUp it works — Zero

aerkain aerkain · Accepted Answer · 2012-03-07T16:48:09

I would guess that the reason is that your rectangle is getting the UP event and (somehow?) not bubbling it up to the canvas. So try to set ishitestvisible to false:

private void BeginDrawing(object sender, System.Windows.Input.MouseButtonEventArgs e)
        {
            _initXPos = e.GetPosition(drawingArea).X;
            _initYPos = e.GetPosition(drawingArea).Y;
            _selectionBox = new SelectionBox ();

            _selectionBox.IsHitTestVisible = false;

            drawingArea.Children.Add(_selectionBox);
            _isDrawing = true;
        }

`

Silverlight : MouseLeftButtonUp is not triggered

2 Answers