In SilverLight Autocomplete box  control, it  takes  some  time  to load  if  very huge data is  bound to it.

So , to increase the  performance level of  the control binding event we  can use the “Populating” event.

Exp:

If  our  requirement  is  to show all names starting  with “Ab” or whatever the  user texts in ,instead  of  binding the  autocompletebox  at the  time  of  page load,

We  can bind it  in  “Populating” event which  will get  all the  names starting  with whatever user types in, which will make population of the autocompletebox  a bit  faster compared  to  binding the  control to all records and enabling filter upon it.

<input:AutoCompleteBox
  Name="CbNames" 
  ValueMemberPath="value"
  ItemsSource="{Binding}"
  Populating="CbNames_Populating"   SelectionChanged="CbNames_SelectionChanged" 
  IsTextCompletionEnabled="True"
  HorizontalAlignment="Left" Margin="83,93,504,0"
  VerticalAlignment="Top" Width="283">
      <input:AutoCompleteBox.ItemTemplate>
         <DataTemplate>
           <TextBlock Text="{Binding value}"> </TextBlock>
               </DataTemplate>
                  </input:AutoCompleteBox.ItemTemplate>
                  </input:AutoCompleteBox>
 
private void CbNames_Populating(object sender, PopulatingEventArgs e)
{
      //bind   the  control  to  a  list
    CbNames.DataContext = listNames;
}