C# WPF binding doesn't take data from Property

I went ahead and created a hello world version for this. Here is the xml. This should simply change the banner when the button is clicked to the text in the text box. I couldn't find a super simple example so I just made one. Obviously there are way more advanced ways to do this but it should make for a simple version to build from.

<Window x:Class="Hello_World.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="350" Width="525">
    <Grid>
        <Label Name="MyLabel" Content="{Binding MyLabel}" HorizontalAlignment="Left" Margin="58,37,0,0" VerticalAlignment="Top" Height="65" Width="423" FontSize="44"/>
        <TextBox Name="MyTextBox" HorizontalAlignment="Left" Height="28" Margin="163,162,0,0" TextWrapping="Wrap" Text="TextBox" VerticalAlignment="Top" Width="163"/>
        <Button Content="Change Banner" HorizontalAlignment="Left" Margin="251,209,0,0" VerticalAlignment="Top" Width="109" Click="Button_Click"/>

    </Grid>
</Window>

Next is the ModelView that implements the INotifyPropertyChanged interface. Note that your properties must be public properties with a getter, setter and backing field. This allows you to call the OnPropetyChanged() method whenever the property is set.

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Hello_World
{
    public class MainViewModel: INotifyPropertyChanged
    {


        private string _myLabel;

        public string MyLabel
        {
            get { return _myLabel; }
            set
            {
                _myLabel = value;
                OnPropertyChanged(nameof(MyLabel));
            }
        }    

        public event PropertyChangedEventHandler PropertyChanged;

        private void OnPropertyChanged(string propetyName)
        {
            if(PropertyChanged != null)
            PropertyChanged(this,new PropertyChangedEventArgs(propetyName));

        }

    }
}

Lastly the MainWindow. Set the DataContext in the main constructor. Note I could have set the DataContext of the main grid and all of its children would inherit the same DataContext. This would keep you from having to set all of the components' individually.

namespace Hello_World
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        private MainViewModel MyViewModel;


        public MainWindow()
        {
            InitializeComponent();
            MyViewModel = new MainViewModel();

            // Here's where I'm setting the object to look at.
            DataContext = MyViewModel;

            // Now I don't need to access the textbox directly.
            MyViewModel.MyLabel = "Hello World";    
        }

        private void Button_Click(object sender, RoutedEventArgs e)
        {
            // Note: ICommand is a more advanced topic.
            MyViewModel.MyLabel = MyTextBox.Text;
        }
    }
}