Console.SetCursorPosition(x, y);

tb.Clear();
        string s = "";
        for (int i = 0; i < mh; i++)
        {
            for (int j = 0; j < mw; j++)
            {
                s += MatrixArray[i, j];
            }
            s += "n";
            tb.Text += s;
        }

public static void MatrixStep(int width, int height, int[] y, int[] l)
    {

        int x;
        thistime = !thistime;

        for (x = 0; x < width; ++x)
        {

            if (x % 11 == 10)
            {

                if (!thistime)
                    continue;

                Console.ForegroundColor = ConsoleColor.White;
            }
            else
            {
                Console.ForegroundColor = ConsoleColor.DarkGreen;
                Console.SetCursorPosition(x, inBoxY(y[x] - 2 - (l[x] / 40 * 2), height));
                Console.Write(R);
                Console.ForegroundColor = ConsoleColor.Green;
            }
            Console.SetCursorPosition(x, y[x]);
            Console.Write(R);
            y[x] = inBoxY(y[x] + 1, height);
            Console.SetCursorPosition(x, inBoxY(y[x] - l[x], height));
            Console.Write(' ');  // Основной фоновый символ в потоке
        }

private void PrintMatrix(int x, int y, char r)
    {
        this.Dispatcher.Invoke((Action)(() =>
        {
            AddText(x, y, r);
            foreach (object myCanvasChild in cConsole.Children)
            {
                var tb = myCanvasChild as TextBlock;
                if (tb == null) return;
                var top = (double)tb.GetValue(Canvas.TopProperty);
                Canvas.SetTop(tb, top);
            }
        }));
    }

    private void AddText(int x, int y, char r)
    {
        Rectangle rct = new Rectangle();
        rct.Fill = Brushes.Black;
        rct.Height = 19;
        rct.Width = 17;
        Canvas.SetTop(rct, 21 * x + 4);
        Canvas.SetLeft(rct, 18 * y);
        cConsole.Children.Add(rct);

        var txt = new TextBlock
        {
            Text = r.ToString(),
            Foreground = tc,
            FontSize = 18,
            FontWeight = FontWeights.Bold,
            FontFamily = new FontFamily("Courier New")
        };
        Canvas.SetTop(txt, 21 * x + 5);
        Canvas.SetLeft(txt, 18 * y + 3);
        cConsole.Children.Add(txt);
    }

using System;
using System.Threading;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;

namespace matrix
{
/// <summary>
///     Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
    {
    private readonly Random rnd = new Random();

    public MainWindow()
        {
        InitializeComponent();
        Task.Factory.StartNew(()=>
            {
            while (true)
            {
                Application.Current.Dispatcher.Invoke(()=>
                    {
                    AddText();
                    foreach (object myCanvasChild in MyCanvas.Children)
                    {
                        var tb = myCanvasChild as TextBlock;
                        if (tb == null) return;
                        var top = (double) tb.GetValue(Canvas.TopProperty);
                        Canvas.SetTop(tb, top + 50);
                    }
                    });
                Thread.Sleep(TimeSpan.FromMilliseconds(300));
            }
            });
        }

    private void AddText()
        {
        var txt = new TextBlock
        {
            Text = $"some message value ={rnd.Next()}",
            Foreground = new SolidColorBrush(Colors.Green)
        };
        Canvas.SetTop(txt, 0);
        MyCanvas.Children.Add(txt);
        }
    }
}

<Window x:Class="matrix.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"
    mc:Ignorable="d"
    Title="MainWindow" Height="350" Width="525">
<Canvas Name="MyCanvas">

</Canvas>