<Window x:Class="WpfApplication2.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:WpfApplication2"
        mc:Ignorable="d"
        Title="MainWindow" Height="350" Width="525">
    <Grid Name="grd">
        <Canvas Name="cnvs" HorizontalAlignment="Center" Height="1276" VerticalAlignment="Center" Width="1550"/>
        <Button x:Name="button" Content="Button" HorizontalAlignment="Left" VerticalAlignment="Top" Width="143" Height="63" Click="button_Click" RenderTransformOrigin="0.5,0.5"/>
    </Grid>
</Window>

private void button_Click(object sender, RoutedEventArgs e)
{
    Point position = button.TranslatePoint(new Point(0, 0), (VisualTreeHelper.GetParent(cnvs) as UIElement));
    grd.Children.Remove(button);
    cnvs.Children.Add(button);
    Canvas.SetLeft(button, position.X);
    Canvas.SetTop(button, position.Y);
}

Point position = grd.TranslatePoint(new Point(0, 0), cnvs);

Point position = button.TranslatePoint(new Point(0, 0), cnvs);