Change font

   
  

<Page xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
  x:Class="Typography_Samp.Page1"
  WindowTitle="Typography Variants Sample">
  <FlowDocument Name="tf1" FontSize="18" ColumnWidth="600.0">
    <Paragraph FontSize="20" Margin="0,0,0,10">Typography Variants Sample</Paragraph>

    <Paragraph Margin="0,0,0,50">
      this is a test
    </Paragraph>

    <Paragraph>
      <StackPanel Orientation="Horizontal" Margin="10" HorizontalAlignment="Center">
        <Button Click="changeArial">Arial</Button>
        <Button Click="changePalatino">Palatino Linotype</Button>
        <Button Click="changeTimes">Times New Roman</Button>
        <Button Click="changeVerdana">Verdana</Button>
      </StackPanel>

      <LineBreak/>
      Normal <Run Typography.Variants="Superscript">superscript</Run>
      <Run Typography.Variants="Subscript">subscript</Run>
      1<Run Typography.Variants="Ordinal">st</Run>
      H<Run Typography.Variants="Inferior">2</Run>
      SO<Run Typography.Variants="Inferior">4</Run>
    </Paragraph>
    
  </FlowDocument>
</Page>

//File:Window.xaml.cs

using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;

namespace Typography_Samp
{

  public partial class Page1 : Page
  {
        public void changeArial(object sender, RoutedEventArgs e)
        {
            tf1.FontFamily = new FontFamily("Arial");
        }

        public void changePalatino(object sender, RoutedEventArgs e)
        {
            tf1.FontFamily = new FontFamily("Palatino Linotype");
        }

        public void changeTimes(object sender, RoutedEventArgs e)
        {
            tf1.FontFamily = new FontFamily("Times New Roman");
        }

        public void changeVerdana(object sender, RoutedEventArgs e)
        {
            tf1.FontFamily = new FontFamily("Verdana");
        }
    }
}