Update ListBox Dynamically when underlying data changed

4 replies. Latest Post by esite on July 3, 2009.

(0)

Participant

754 points

Update ListBox Dynamically when underlying data changed

07-02-2009 6:27 AM |

A rookie question here I am sure. I adapted this tutorial as an example (http://silverlight.net/learn/tutorials/databinding.aspx).

When I delete a record from the bound data of ListBox the list box is not updated. I have no idea how to make it change it's datasource once it is deleted.

So I adapted the tutorial to have a delete chapter button like this and the Listbox to bind TwoWay:

private void btnDeleteList_Click(object sender, RoutedEventArgs e)
{
    currentBook.Chapters.Remove(Chapters.SelectedItem.ToString());
    //Chapters.ItemsSource = Chapters;
    //Chapters.SetBinding(ListBox.DataContextProperty, new Binding("Chapters"));
}

I would expect or know how to be able to update the Listbox immediately once I click delete the Chapter.

Any help would be greatly appreciated.

Thanks.

Please mark replies as answers if they answered your question.

Anton Swanevelder
eSite Solutions

varshavmane

Contributor

6263 points

1,489 Posts

Re: Update ListBox Dynamically when underlying data changed

07-02-2009 7:01 AM |

Use ObservableCollection.

Have a quick look around - see if this link helps...

HTH Smile

Please "Mark as Answer" if this post answered your question. :)
Visit my Blog: http://varshavmane.blogspot.com/

HarshBar...

Star

9908 points

1,719 Posts

Re: Update ListBox Dynamically when underlying data changed

07-02-2009 7:14 AM |

I had modified few things in your sample.

You can try this.

//Xaml file

//Code behind:

    public partial class Page : UserControl
    {
        ObservableCollection users;
     
        public Page()
        {
            InitializeComponent();

  users = new ObservableCollection();
            users.Add(new User() { UserName = "Harsh" });
            users.Add(new User() { UserName = "Nimesh" });
            users.Add(new User() { UserName = "Test" });
            users.Add(new User() { UserName = "Test1" });
            users.Add(new User() { UserName = "Test2" });

            Chapters.ItemsSource = users;


}

        private void btnDeleteList_Click(object sender, RoutedEventArgs e)
        {
            if (users.Count > 2)
            {
                users.RemoveAt(2);
            }
        } 
       
    


 

    }

    public class User: INotifyPropertyChanged
    {
       private string   username  ;

    public string  UserName
    {
         get 
         {
             return  username ; 
         }
         set 
         {
            

              username  = value;
                 onPropertyChanged( this ,  "UserName" ) ;
             }
        }

        public event   PropertyChangedEventHandler PropertyChanged  ;

    private void  onPropertyChanged( object  sender ,  string  propertyName)
    {

         if  ( this.PropertyChanged != null )
        {
            PropertyChanged(sender, new  PropertyChangedEventArgs(propertyName)) ;
         }
    }
    }