title: How to force AutoCompleteBox control to populate the ItemSource only after n chars are entered?
body: <p>Is it possible to force AutoCompleteBox control in SilverLight application to start obtaining ItemSource data only after n chars are entered (the data with the filtering mode StartsWith? </p>
  
  <p>Thanks,</p>
  
  <p>Here is the way I bind my ItemsSources (Basically there is a comboBox which stands for Stetes. And once a state is selected I set itemsSource of the AutoCompleteBox control. But it seems even before I type 3 chars the Db call is done -checked by SQL Profiler-):</p>
  
  <p>This is my XAML :</p>
  
  <pre><code>&lt;input:AutoCompleteBox Name="autoCompCity" Grid.Column="1" Grid.Row="2" 
  HorizontalAlignment="Left"  VerticalAlignment="Bottom" Width="180"
  MinimumPopulateDelay="10" MinimumPrefixLength="3" 
  FilterMode="StartsWith" MaxDropDownHeight="150"  
  ValueMemberPath="CityName" Text="Enter city" 
  IsTextCompletionEnabled="True"&gt;&lt;/input:AutoCompleteBox&gt;
  </code></pre>
  
  <p>And my code-behind:</p>
  
  <pre><code>private void comboState_SelectionChanged(object sender
  , SelectionChangedEventArgs e)
       {
        if (SelectedState== null)
         return;
         BindCityAutoCompleteBox();
       }
  
  
  private void BindCityAutoCompleteBox()
   {
    autoCompCity.IsEnabled = true;
    autoCompCity.ItemsSource = GetCityList(SelectedState, SelectedCountry);
   }
  </code></pre>