Canvas

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace WPF_GenesteLussen
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }

        private void Button_Click(object sender, RoutedEventArgs e)
        {
            int Rij = Convert.ToInt32(txtRij.Text);
            int Kolom = Convert.ToInt32(txtKolom.Text);
            Random rand = new Random();

            cnvCan.Children.Clear();
            for (int i = 0; i < Rij; i++)
            {
                for (int j = 0; j < Kolom; j++)
                {
                    Rectangle r = new Rectangle();
                    r.Width = 20;
                    r.Height = r.Width;
                    r.Stroke = new SolidColorBrush(Color.FromRgb((byte)(rand.Next(255)), (byte)rand.Next(255), (byte)(rand.Next(255))));
                    r.Margin = new Thickness(i * r.Height, j * r.Height, 0,0);
                    r.Width = 15;
                    r.Height = r.Width;
                    cnvCan.Children.Add(r);

                }
            }
        }
    }
}