WPF C#

    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="WPF" Height="300" Width="300">
    
                         Name="textBox1" TextAlignment="Left" TextWrapping="Wrap" 
                 VerticalScrollBarVisibility="Auto">
            Default starting text.
        
        
            Set Text
            Select All
            Clear
            Prepend
            Insert
            Append
            Cut
            Paste
            Undo
        
    


//File:Window.xaml.cs
using System.Windows;
using System.Windows.Controls;
namespace WpfApplication1
{
    public partial class Window1 : Window
    {
        public Window1()
        {
            InitializeComponent();
        }
        private void AppendButton_Click(object sender, RoutedEventArgs e)
        {
            textBox1.AppendText("text");
        }
        private void ClearButton_Click(object sender, RoutedEventArgs e)
        {
            textBox1.Clear();
        }
        private void CutButton_Click(object sender, RoutedEventArgs e)
        {
            if (textBox1.SelectionLength == 0)
            {
                MessageBox.Show("Select text to cut first.", Title);
            }
            else
            {
                MessageBox.Show("Cut: " + textBox1.SelectedText, Title);
                textBox1.Cut();
            }
        }
        private void InsertButton_Click(object sender, RoutedEventArgs e)
        {
            textBox1.Text = textBox1.Text.Insert(textBox1.CaretIndex, "text");
        }
        private void PasteButton_Click(object sender, RoutedEventArgs e)
        {
            textBox1.Paste();
        }
        private void PrependButton_Click(object sender, RoutedEventArgs e)
        {
            textBox1.Text = textBox1.Text.Insert(0, "Prepend");
        }
        private void SelectAllButton_Click(object sender, RoutedEventArgs e)
        {
            textBox1.SelectAll();
            textBox1.Focus();
        }
        private void TextButton_Click(object sender, RoutedEventArgs e)
        {
            textBox1.Text = "new value";
        }
        private void UndoButton_Click(object sender, RoutedEventArgs e)
        {
            textBox1.Undo();
        }
    }
}