Inotify propertychanged not updating - windows-phone-7

Question

I have a class which implements inotifypropertychaned.
public class Item : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
private string _name = string.Empty;
public string Name
{
get
{
return _name;
}
set
{
this._name = value;
onPropertyChanged(this, "Name");
}
}
private void onPropertyChanged(object sender, string property)
{
PropertyChangedEventHandler handler = PropertyChanged;
if (handler != null)
{
handler(sender, new PropertyChangedEventArgs(property));
}
}
}
here in UI i ve a textbox where a textchanged event when the length exceeds and updates the UI(grid) which binds the observable collection of the above mentioned class. but the UI is not updating.
ObservableCollection<Item> lstItem = null;
private void textBox1_TextChanged(object sender, EventArgs e)
{
try
{
if (textBox1.Text.Length > 4)
{
Item obj = new Item();
obj.Name = textBox1.Text;
lstItem = new ObservableCollection<Item>();
dataGridView1.DataSource = lstItem;
}
}
catch (Exception ex)
{
Debug.WriteLine(ex.Message.ToString());
}
}
Thanks.

Answer 1

Look at this code:
Item obj = new Item();
obj.Name = textBox1.Text;
lstItem = new ObservableCollection<Item>();
dataGridView1.DataSource = lstItem;
You're setting the data source to an empty collection each time, and you're creating a new Item and then throwing it away again. Did you intend to add the item to the collection?
lstItem = new ObservableCollection<Item> { obj };
(It's not really clear whether you should be creating a new collection or even a new item - perhaps you should be using something like:
lstItem[0].Name = textBox1.Text;
instead?)