Best way for add thousans items to listbox without freezing ui in wpf

Question

Hello guys.
What is the best way for add thousands items (or even more) to Listbox without freezing UI.
I search many post in the web but I don't understand how this posts writer wrote that code.
I realized that ObservableCollection can contain 1000 items or even more and show that items to listbox just for few second without freezing UI but I don't Know how can I use that!
Can you guys give me an example.
thanks.

Answer 1

If you bind an observablecollection you can add items to that from a background thread.  Then bind that to the itemssource.  I usually new up an observablecollection, add the items then set the bound property to  that.
But I avoid thousands of items. 
You should provide some sort of filter mechanism the user chooses a category or whatever and then fill with a maximum of 300 items.
Users simply can't work with thousands of items.
It is usually reading the data out  a database which takes the time rather than creating objects to bind.
Hence this:
protected async override void GetData()
ThrobberVisible = Visibility.Visible;
ObservableCollection<CustomerVM> _customers = new ObservableCollection<CustomerVM>();
var customers = await (from c in db.Customers
orderby c.CustomerName
select c).ToListAsync();
foreach (Customer cust in customers)
_customers.Add(new CustomerVM { IsNew = false, TheEntity = cust });
Customers = _customers;
RaisePropertyChanged("Customers");
ThrobberVisible = Visibility.Collapsed;
That's making an asynchronous entity framework call.
A list of customers is obtained.
These are then wrapped in a customer viewmodel each.
Finally the observablecollection Customers is set to this new collection and propertychanged raised to notify the view.
The itemssource of a datagrid is bound to Customers.
Hope that helps.
Recent Technet articles: Property List Editing;
Dynamic XAML