title: Data Binding doesn't work in xaml
body: <p><em>I try to use binding to display Hi in  the Text content.
  However, when clicking the button, it doesn't work.
  Could someone help me to solve the problem?
  Thanks.</em></p>
  
  <p><em>1.XAML CODE :</em></p>
  
  <pre><code>&lt;Window x:Class="Wpftest.binding.Window0"                          
          xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
          xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
          Title="Window0" Height="300" Width="300"&gt;
     &lt;Grid&gt;
        &lt;TextBox x:Name="textBox2" VerticalAlignment="Top" Width="168" 
                 Text="{Binding Source= stu,  Path= Name, Mode=TwoWay}"/&gt;
     &lt;/Grid&gt;
  &lt;/Window&gt;
  </code></pre>
  
  <p><em>2.Class :</em> </p>
  
  <pre><code>namespace Wpftest.binding.Model
  {
     public class student : INotifyPropertyChanged 
     {
        public event PropertyChangedEventHandler PropertyChanged;        
        private string name;
  
        public string Name
        {
           get { return name; }
  
           set { name = value;
  
                if(this.PropertyChanged != null)
                {
                   this.PropertyChanged.Invoke(this, new     
                   PropertyChangedEventArgs("Name"));
                }
           }
         }
      }
  }
  </code></pre>
  
  <p><em>3.XAML.cs:</em> </p>
  
  <pre><code> namespace Wpftest.binding
      {
          public partial class Window0 : Window
          {
              student stu;
              public Window0()
              {
                  InitializeComponent();
                  stu = new student();
             }
  
              private void button_Click(object sender, RoutedEventArgs e)
              {
                  stu.Name += "Hi!";
              }
          }
      }
  </code></pre>