Dynamically adding and moving ellipses using WPF

Question

I'm using WPF and having trouble dynamically/programatically adding ellipses to my grid.

I'm dynamically allocating and placing ellipses inside myGrid. Trouble is the position on the ellipses don't change. I'm using Canvas.SetLeft and SetTop, but the ellipses still seem stuck.

Here is the code for dynamic allocation :

{
...

       Ellipse el = new Ellipse();
                    RadialGradientBrush b = new RadialGradientBrush();
                    b.RadiusX = r * 10.0f;
                    b.RadiusY = r * 10.0f;
                    b.GradientOrigin = new Point(0.5f, 0.5f);
                    b.GradientOrigin = new Point(0.5f, 0.5f);
                    b.GradientStops.Add(new GradientStop(Colors.Green, 0.0));
                    b.GradientStops.Add(new GradientStop(Colors.Blue, 1.0));
                    el.Width = 5.0f + r * 20.0f;
                    el.Height = 5.0f + r * 20.0f;
                    el.Stroke = b;
                    SetEllipsePosition(el, p);
 this.myGrid.Children.Add(el);

...


}
        private void SetEllipsePosition(FrameworkElement ellipse, Point j)
        {
            Canvas.SetLeft(ellipse, j.X);
            Canvas.SetTop(ellipse, j.Y);
        }





                    <Grid Height="480" Name="myGrid" Width="640">
                        <GroupBox Header="Pattern" Height="117" HorizontalAlignment="Left" Margin="10,564,0,0" Name="groupBox1" VerticalAlignment="Top" Width="238"></GroupBox>

                        <Button Content="Button" Height="23" HorizontalAlignment="Left" Margin="33,30,0,0" Name="button1" VerticalAlignment="Top" Width="75" Click="button1_Click_1" />
                        <Grid Margin="6,507,408,-121">
                            <RadioButton Content="Lines" Height="16" HorizontalAlignment="Left" Margin="15,18,0,0" Name="rbLines" VerticalAlignment="Top" GroupName="RenderStyles" />
                            <RadioButton Content="Circles" Height="16" HorizontalAlignment="Left" Margin="15,49,0,0" Name="rbCircles" VerticalAlignment="Top" GroupName="RenderStyles" />
                        </Grid>
                    </Grid>

BigL · Accepted Answer · 2011-12-11 21:19:20Z

3

The problem is that you are using a Grid but setting Canvas properties, you could add a Canvas into the Grid and draw you ellipses on the Canvas ( add them to the Canvases children), and then it would work.

Or you could use the Margin property of your ellipse to set it's position on the Grid

answered Dec 11, 2011 at 21:19

BigL

1,6311 gold badge11 silver badges10 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Oliver · Accepted Answer · 2011-12-12 01:51:23Z

1

Canvas.Left and Canvas.Top are attached properties: you set them only if your UI element is going to be contained in a Canvas; and only when it is on a Canvas will those properties be used (by the Canvas layout manager). Same with attached properties from Grid (such as Grid.Column to tell the Grid parent in what column the UI elements "wants" to be), Panel (Panel.ZIndex to tell the Panel parent at what z index the UI element should be put), etc.

answered Dec 12, 2011 at 1:51

Oliver

30k12 gold badges81 silver badges114 bronze badges

Collectives™ on Stack Overflow

Dynamically adding and moving ellipses using WPF

2 Answers 2

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related