WPF C# Tutorial

using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
using System.Windows.Media;
    class MainClass : Window
    {
        TextBox txtboxBegin = new TextBox();
        TextBox txtboxEnd = new TextBox();
        Label lblLifeYears  = new Label();
        [STAThread]
        public static void Main()
        {
            Application app = new Application();
            app.Run(new MainClass());
        }
        public MainClass()
        {
            SizeToContent = SizeToContent.WidthAndHeight;
            ResizeMode = ResizeMode.CanMinimize;
            Grid grid = new Grid();
            Content = grid;
            for (int i = 0; i < 2; i++)
            {
                RowDefinition rowdef = new RowDefinition();
                rowdef.Height = GridLength.Auto;
                grid.RowDefinitions.Add(rowdef);
            }
            for (int i = 0; i < 2; i++)
            {
                ColumnDefinition coldef = new ColumnDefinition();
                coldef.Width = GridLength.Auto;
                grid.ColumnDefinitions.Add(coldef);
            }
            Label lbl = new Label();
            lbl.Content = "Begin Date: ";
            grid.Children.Add(lbl);
            Grid.SetRow(lbl, 0);
            Grid.SetColumn(lbl, 0);
            txtboxBegin.Text = new DateTime(1980, 1, 1).ToShortDateString();
            txtboxBegin.TextChanged += TextBoxOnTextChanged;
            grid.Children.Add(txtboxBegin);
            Grid.SetRow(txtboxBegin, 0);
            Grid.SetColumn(txtboxBegin, 1);
            lbl = new Label();
            lbl.Content = "End Date: ";
            grid.Children.Add(lbl);
            Grid.SetRow(lbl, 1);
            Grid.SetColumn(lbl, 0);
            txtboxEnd.TextChanged += TextBoxOnTextChanged;
            grid.Children.Add(txtboxEnd);
            Grid.SetRow(txtboxEnd, 1);
            Grid.SetColumn(txtboxEnd, 1);
            Thickness thick = new Thickness(5); // ~1/20 inch.
            grid.Margin = thick;
            foreach (Control ctrl in grid.Children)
                ctrl.Margin = thick;
            txtboxBegin.Focus();
            txtboxEnd.Text = DateTime.Now.ToShortDateString();
        }
        void TextBoxOnTextChanged(object sender, TextChangedEventArgs args)
        {
            Console.WriteLine(txtboxBegin.Text);
            lblLifeYears.Content = "string";
        }
    }