【WPF】グリッド状の模様を描く　その(1) CanvasのChildrenに線を追加する

<UserControl x:Class="WpfMyGridLesson.MyGridView"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
             mc:Ignorable="d" 
             d:DesignHeight="300" d:DesignWidth="300"
             Loaded="UserControl_Loaded"
             SizeChanged="UserControl_SizeChanged">

    <!-- 線のスタイル -->
    <UserControl.Resources>
        <Style x:Key="GridLineStyle" TargetType="Line">
            <Setter Property="StrokeThickness" Value="1" />
            <Setter Property="Stroke" Value="LightGray" />
            <Setter Property="SnapsToDevicePixels" Value="True" />
        </Style>
    </UserControl.Resources>
    <Grid>
        <!-- 描画用のキャンバス -->
        <Canvas Name="myCanvas"/>
    </Grid>
</UserControl>

namespace WpfMyGridLesson
{
    /// <summary>
    /// MyGridView.xaml の相互作用ロジック
    /// </summary>
    public partial class MyGridView : UserControl
    {
        private const int GRID_SIZE = 20;

        public MyGridView()
        {
            InitializeComponent();
        }

        private void UserControl_Loaded(object sender, RoutedEventArgs e)
        {
            BuildView();
        }

        private void UserControl_SizeChanged(object sender, SizeChangedEventArgs e)
        {
            BuildView();
        }

        // キャンバスに線を描画する
        private void BuildView()
        {
            myCanvas.Children.Clear();


            Style lineStyle = this.FindResource("GridLineStyle") as Style;

            for (int i = 0; i < this.ActualWidth; i += GRID_SIZE)
            {
                Line line = new Line()
                {
                    X1 = i,
                    Y1 = 0,
                    X2 = i,
                    Y2 = this.ActualHeight,
                    Style = lineStyle
                };

                myCanvas.Children.Add(line);
            }

            for (int i = 0; i < this.ActualHeight; i += GRID_SIZE)
            {
                Line line = new Line()
                {
                    X1 = 0,
                    Y1 = i,
                    X2 = this.ActualWidth,
                    Y2 = i,
                    Style = lineStyle
                };

                myCanvas.Children.Add(line);
            }
        }
    }
}

<Window x:Class="WpfMyGridLesson.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:my="clr-namespace:WpfMyGridLesson"
        Title="MainWindow" Height="350" Width="525">
    <Grid>
        <!-- ユーザーコントロールを配置 -->
        <my:MyGridView></my:MyGridView>
    </Grid>
</Window>