Question

I have a class named Data with some public members: Name, Age, Address.

I have also window with text boxes Name, Age, Address.

The Data object can change any time.

How can I bind the Data object to the text boxes and follow after object changes?

I know there is INotifyPropertyChanged and “dependency-properties” but I do not know how to use them.

Edit

public class MyData : INotifyPropertyChanged
{
  private string _name;

  public string Name
  {
    get
    {
      return _name;
    }
    set
    {
      if (_name != value)
      {
        _name = value;
        OnPropertyChnged("Name");
      }
    }
   }
   public event PropertyChangedEventHandler PropertyChanged;

   protected void OnPropertyChanged(string name)
   {
     ProppertyChangedEventHandler handler = PropertyChanged;
     if (handler != null) handler(this, new PropertyChangedEventArgs(name));
   }
}

XAML code:

xmlns:myApp="clr-namespace:MyApp"
<Window.Resources><myApp:MyData x:key = data/></WindowResources>
<TextBox><TextBox.Text><Binding Source="{StaticResource data}" Path="Name" UpdateSourceTrigger="PropertyChanged"/></TextBox.Text></TextBox>

---

class OtherClass
{
  private MyData data;
  //the window that have the binding textbox
  private MyWindow window;
  public OtherClass()
  {
    data = new MyData();
    data.Name = "new name"
    window = new MyWindow();
    window.show();
  }
}

Answer 1

This link from MSDN explains it well.

MSDN link is dead, adding link to a similar article.

When your class property is changed, your property should raise a OnPropertyChanged event with the name of the property so that the View knows to refresh it’s binding.

    public String Name
    {
        get { return _name; }
        set 
        {
            if (_name != value)
            {
                _name = value;
                this.OnPropertyChanged("Name");
            }
        }
    }

And your textbox should have a binding such as:

<TextBox Text="{Binding Name}"/>

I have a ViewModelBase class which is where I have implemented my OnPropertyChandedEvent for all derived models to call:

    /// <summary>
    /// An event for when a property has changed.
    /// </summary>
    public event PropertyChangedEventHandler PropertyChanged;

    /// <summary>
    /// Virtual method to call the Property Changed method
    /// </summary>
    /// <param name="propertyName">The name of the property which has changed.</param>
    protected virtual void OnPropertyChanged(String propertyName)
    {
        if (this.PropertyChanged != null)
            this.PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
    }