Silverlight label display style

using System;
using System.ComponentModel;
using System.Windows.Media;
using System.Windows.Controls;
using System.Windows.Documents;

namespace SilverlightApplicationTextTransform
{
    public partial class MainPage : UserControl, INotifyPropertyChanged
    {
        #region ViewModelProperty: MainContent
        private object _mainContent;
        public object MainContent
        {
            get
            {
                return _mainContent;
            }
            set
            {
                _mainContent = value;
                OnPropertyChanged("MainContent");
            }
        }
        #endregion
 
        public MainPage()
        {
            InitializeComponent();

            DataContext = this;

        }

        private char[] textToDisplay = null;
        private int length = 0;

        private void textBoxTextToDisplay_TextChanged(object sender, TextChangedEventArgs e)
        {
            textToDisplay = textBoxTextToDisplay.Text.ToCharArray();
            length = textToDisplay.Length;
            
            TextBlock tb = new TextBlock();
            tb.FontFamily = new FontFamily("Courier");
            tb.FontSize = 15;
            int fontSize = 15;

            Run[] runLabel = new Run[length];
            bool par = false; // to test if the length is odd or even
            
            if (length % 2 == 0)
            {
                par = true;
            }
            
            for (int i = 0; i < length / 2; i++)
            {
                runLabel[i] = new Run();
                runLabel[i].Text = Convert.ToString(textToDisplay[i]);
                runLabel[i].FontSize = fontSize;
                tb.Inlines.Add(runLabel[i]);

                if ((par == true) && (i == (length / 2) - 1))
                {
                }
                else
                {
                    fontSize += 3;
                }
            }
            for (int i = length / 2; i < length; i++)
            {
                runLabel[i] = new Run();
                runLabel[i].Text = Convert.ToString(textToDisplay[i]);
                runLabel[i].FontSize = fontSize;
                tb.Inlines.Add(runLabel[i]);
                fontSize -= 3;
            }
            
            MainContent = tb;
        }

        #region INotifiedProperty Block
        public event PropertyChangedEventHandler PropertyChanged;

        protected void OnPropertyChanged(string propertyName)
        {
            PropertyChangedEventHandler handler = PropertyChanged;

            if (handler != null)
            {
                handler(this, new PropertyChangedEventArgs(propertyName));
            }
        }
        #endregion
 
    }
}

<sdk:Label Height="Auto" Name="labelDisplay" Width="Auto">
    <ContentControl Content="{Binding MainContent}"/>
</sdk:Label>