private static void OnSearchModePropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
AutoCompleteTextBox source = d as AutoCompleteTextBox;
AutoCompleteSearchMode mode = (AutoCompleteSearchMode)e.NewValue;
if (mode != AutoCompleteSearchMode.Contains &&
mode != AutoCompleteSearchMode.ContainsCaseSensitive &&
mode != AutoCompleteSearchMode.ContainsOrdinal &&
mode != AutoCompleteSearchMode.ContainsOrdinalCaseSensitive &&
mode != AutoCompleteSearchMode.Custom &&
mode != AutoCompleteSearchMode.Equals &&
mode != AutoCompleteSearchMode.EqualsCaseSensitive &&
mode != AutoCompleteSearchMode.EqualsOrdinal &&
mode != AutoCompleteSearchMode.EqualsOrdinalCaseSensitive &&
mode != AutoCompleteSearchMode.None &&
mode != AutoCompleteSearchMode.StartsWith &&
mode != AutoCompleteSearchMode.StartsWithCaseSensitive &&
mode != AutoCompleteSearchMode.StartsWithOrdinal &&
mode != AutoCompleteSearchMode.StartsWithOrdinalCaseSensitive)
{
source.SetValue(e.Property, e.OldValue);
throw new ArgumentException("", "value");
}
// Sets the filter predicate for the new value
AutoCompleteSearchMode newValue = (AutoCompleteSearchMode)e.NewValue;
source.TextFilter = AutoCompleteSearch.GetFilter(newValue);
}
/// <summary>
/// Performs text completion, if enabled, and a lookup on the underlying
/// item values for an exact match. Will update the SelectedItem value.
/// </summary>
/// <param name="userInitiated">A value indicating whether the operation
/// was user initiated. Text completion will not be performed when not
/// directly initiated by the user.</param>
private void UpdateTextCompletion(bool userInitiated)
{
// By default this method will clear the selected value
object newSelectedItem = null;
string text = Text;
// Text search is StartsWith explicit and only when enabled, in
// line with WPF's ComboBox lookup. When in use it will associate
// a Value with the Text if it is found in ItemsSource. This is
// only valid when there is data and the user initiated the action.
if (View.Count > 0)
{
if (IsTextCompletionEnabled && TextBox != null && userInitiated)
{
int currentLength = TextBox.Text.Length;
int selectionStart = TextBox.SelectionStart;
if (selectionStart == text.Length && selectionStart > TextSelectionStart)
{
// When the SearchMode dependency property is set to
// either StartsWith or StartsWithCaseSensitive, the
// first item in the view is used. This will improve
// performance on the lookup. It assumes that the
// SearchMode the user has selected is an acceptable
// case sensitive matching function for their scenario.
object top = SearchMode == AutoCompleteSearchMode.StartsWith || SearchMode == AutoCompleteSearchMode.StartsWithCaseSensitive
? View[0]
: TryGetMatch(text, View, AutoCompleteSearch.GetFilter(AutoCompleteSearchMode.StartsWith));
// If the search was successful, update SelectedItem
if (top != null)
{
newSelectedItem = top;
string topString = FormatValue(top);
// Only replace partially when the two words being the same
int minLength = Math.Min(topString.Length, Text.Length);
if (AutoCompleteSearch.Equals(Text.Substring(0, minLength), topString.Substring(0, minLength)))
{
// Update the text
UpdateTextValue(topString);
// Select the text past the user's caret
TextBox.SelectionStart = currentLength;
TextBox.SelectionLength = topString.Length - currentLength;
}
}
}
}
else
{
// Perform an exact string lookup for the text. This is a
// design change from the original Toolkit release when the
// IsTextCompletionEnabled property behaved just like the
// WPF ComboBox's IsTextSearchEnabled property.
//
// This change provides the behavior that most people expect
// to find: a lookup for the value is always performed.
newSelectedItem = TryGetMatch(text, View, AutoCompleteSearch.GetFilter(AutoCompleteSearchMode.EqualsCaseSensitive));
}
}
// Update the selected item property
SelectedItem = newSelectedItem;
// Restore updates for TextSelection
if (IgnoreTextSelectionChange)
{
IgnoreTextSelectionChange = false;
if (TextBox != null)
{
TextSelectionStart = TextBox.SelectionStart;
}
}
}