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copied!<p>Also found the <a href="http://weblogs.asp.net/okloeten/archive/2007/11/12/5088649.aspx" rel="nofollow">AutoFilteredComboBox</a> to be very simple to work with. Though I have made some changes:</p> <ul> <li>Removed use of DependencyPropertyDescriptor to avoid memory leak of combobox-objects</li> <li>Introduced FilterItem-event and FilterList-event to allow one to customize the filtering</li> <li>Changed default filtering from starts-with-string to contains-string</li> <li>Removed support of having IsTextSearchEnabled enabled</li> <li>Shows dropdown as soon one changes the search string, so search result is displayed</li> </ul> <p>Example of how it is used:</p> <pre><code><Controls:AutoFilteredComboBox ItemsSource="{Binding ViewModel.AvailableItems}" SelectedValue="{Binding ViewModel.SelectedItem, Mode=TwoWay}" IsEditable="True" IsTextSearchEnabled="False"/> </code></pre> <p>Improved version of AutoFilteredComboBox:</p> <pre><code>public class AutoFilteredComboBox : ComboBox { bool _ignoreTextChanged; string _currentText; /// <summary> /// Creates a new instance of <see cref="AutoFilteredComboBox" />. /// </summary> public AutoFilteredComboBox() { if (System.ComponentModel.DesignerProperties.GetIsInDesignMode(this)) return; } public event Func<object, string, bool> FilterItem; public event Action<string> FilterList; #region IsCaseSensitive Dependency Property /// <summary> /// The <see cref="DependencyProperty"/> object of the <see cref="IsCaseSensitive" /> dependency property. /// </summary> public static readonly DependencyProperty IsCaseSensitiveProperty = DependencyProperty.Register("IsCaseSensitive", typeof(bool), typeof(AutoFilteredComboBox), new UIPropertyMetadata(false)); /// <summary> /// Gets or sets the way the combo box treats the case sensitivity of typed text. /// </summary> /// <value>The way the combo box treats the case sensitivity of typed text.</value> [Description("The way the combo box treats the case sensitivity of typed text.")] [Category("AutoFiltered ComboBox")] [DefaultValue(true)] public bool IsCaseSensitive { [System.Diagnostics.DebuggerStepThrough] get { return (bool)this.GetValue(IsCaseSensitiveProperty); } [System.Diagnostics.DebuggerStepThrough] set { this.SetValue(IsCaseSensitiveProperty, value); } } #endregion #region DropDownOnFocus Dependency Property /// <summary> /// The <see cref="DependencyProperty"/> object of the <see cref="DropDownOnFocus" /> dependency property. /// </summary> public static readonly DependencyProperty DropDownOnFocusProperty = DependencyProperty.Register("DropDownOnFocus", typeof(bool), typeof(AutoFilteredComboBox), new UIPropertyMetadata(false)); /// <summary> /// Gets or sets the way the combo box behaves when it receives focus. /// </summary> /// <value>The way the combo box behaves when it receives focus.</value> [Description("The way the combo box behaves when it receives focus.")] [Category("AutoFiltered ComboBox")] [DefaultValue(false)] public bool DropDownOnFocus { [System.Diagnostics.DebuggerStepThrough] get { return (bool)this.GetValue(DropDownOnFocusProperty); } [System.Diagnostics.DebuggerStepThrough] set { this.SetValue(DropDownOnFocusProperty, value); } } #endregion #region | Handle focus | /// <summary> /// Invoked whenever an unhandled <see cref="UIElement.GotFocus" /> event /// reaches this element in its route. /// </summary> /// <param name="e">The <see cref="RoutedEventArgs" /> that contains the event data.</param> protected override void OnGotFocus(RoutedEventArgs e) { base.OnGotFocus(e); if (this.ItemsSource != null && this.DropDownOnFocus) { this.IsDropDownOpen = true; } } #endregion public override void OnApplyTemplate() { base.OnApplyTemplate(); AddHandler(TextBox.TextChangedEvent, new TextChangedEventHandler(OnTextChanged)); KeyUp += AutoFilteredComboBox_KeyUp; this.IsTextSearchEnabled = false; } void AutoFilteredComboBox_KeyUp(object sender, KeyEventArgs e) { if (e.Key == Key.Down) { if (this.IsDropDownOpen == true) { // Ensure that focus is given to the dropdown list if (Keyboard.FocusedElement is TextBox) { Keyboard.Focus(this); if (this.Items.Count > 0) { if (this.SelectedIndex == -1 || this.SelectedIndex==0) this.SelectedIndex = 0; } } } } if (Keyboard.FocusedElement is TextBox) { if (e.OriginalSource is TextBox) { // Avoid the automatic selection of the first letter (As next letter will cause overwrite) TextBox textBox = e.OriginalSource as TextBox; if (textBox.Text.Length == 1 && textBox.SelectionLength == 1) { textBox.SelectionLength = 0; textBox.SelectionStart = 1; } } } } #region | Handle filtering | private void RefreshFilter() { if (this.ItemsSource != null) { Action<string> filterList = FilterList; if (filterList != null) { filterList(_currentText); } else { ICollectionView view = CollectionViewSource.GetDefaultView(this.ItemsSource); view.Refresh(); } this.SelectedIndex = -1; // Prepare so arrow down selects first this.IsDropDownOpen = true; } } private bool FilterPredicate(object value) { // We don't like nulls. if (value == null) return false; // If there is no text, there's no reason to filter. if (string.IsNullOrEmpty(_currentText)) return true; Func<object, string, bool> filterItem = FilterItem; if (filterItem != null) return filterItem(value, _currentText); if (IsCaseSensitive) return value.ToString().Contains(_currentText); else return value.ToString().ToUpper().Contains(_currentText.ToUpper()); } #endregion protected override void OnSelectionChanged(SelectionChangedEventArgs e) { try { _ignoreTextChanged = true; // Ignore the following TextChanged base.OnSelectionChanged(e); } finally { _ignoreTextChanged = false; } } /// <summary> /// Called when the source of an item in a selector changes. /// </summary> /// <param name="oldValue">Old value of the source.</param> /// <param name="newValue">New value of the source.</param> protected override void OnItemsSourceChanged(IEnumerable oldValue, IEnumerable newValue) { if (newValue != null) { ICollectionView view = CollectionViewSource.GetDefaultView(newValue); if (FilterList == null) view.Filter += this.FilterPredicate; } if (oldValue != null) { ICollectionView view = CollectionViewSource.GetDefaultView(oldValue); view.Filter -= this.FilterPredicate; } base.OnItemsSourceChanged(oldValue, newValue); } private void OnTextChanged(object sender, TextChangedEventArgs e) { if (_ignoreTextChanged) return; _currentText = Text; if (!this.IsTextSearchEnabled) { this.RefreshFilter(); } } </code></pre>

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