1 using System;
  2 using System.Collections;
  3 using System.ComponentModel;
  4 using System.Diagnostics;
  5 using System.Windows;
  6 using System.Windows.Controls;
  7 using System.Windows.Data;
  8 
  9 namespace WHQ.QA.Client.Windows.Controls
 10 {
 11 public class AutoFilteredComboBox : ComboBox
 12 {
 13 private int _silenceEvents;
 14 
 15 /// <summary>
 16 ///     Creates a new instance of <see cref="AutoFilteredComboBox" />.
 17 /// </summary>
 18 public AutoFilteredComboBox()
 19 {
 20 DependencyPropertyDescriptor textProperty = DependencyPropertyDescriptor.FromProperty(
 21 TextProperty, typeof(AutoFilteredComboBox));
 22 textProperty.AddValueChanged(this, OnTextChanged);
 23 RegisterIsCaseSensitiveChangeNotification();
 24 IsEditable = true;
 25 }
 26 
 27 #region IsCaseSensitive Dependency Property
 28 
 29 /// <summary>
 30 ///     The <see cref="DependencyProperty" /> object of the <see cref="IsCaseSensitive" /> dependency property.
 31 /// </summary>
 32 public static readonly DependencyProperty IsCaseSensitiveProperty =
 33 DependencyProperty.Register("IsCaseSensitive", typeof(bool), typeof(AutoFilteredComboBox),
 34 new UIPropertyMetadata(false));
 35 
 36 /// <summary>
 37 ///     Gets or sets the way the combo box treats the case sensitivity of typed text.
 38 /// </summary>
 39 /// <value>The way the combo box treats the case sensitivity of typed text.</value>
 40 [Description("The way the combo box treats the case sensitivity of typed text.")]
 41 [Category("AutoFiltered ComboBox")]
 42 [DefaultValue(true)]
 43 public bool IsCaseSensitive
 44 {
 45 [DebuggerStepThrough]
 46 get { return (bool)GetValue(IsCaseSensitiveProperty); }
 47 [DebuggerStepThrough]
 48 set { SetValue(IsCaseSensitiveProperty, value); }
 49 }
 50 
 51 protected virtual void OnIsCaseSensitiveChanged(object sender, EventArgs e)
 52 {
 53 if (IsCaseSensitive)
 54 IsTextSearchEnabled = false;
 55 
 56 RefreshFilter();
 57 }
 58 
 59 private void RegisterIsCaseSensitiveChangeNotification()
 60 {
 61 DependencyPropertyDescriptor.FromProperty(IsCaseSensitiveProperty, typeof(AutoFilteredComboBox))
 62 .AddValueChanged(
 63 this, OnIsCaseSensitiveChanged);
 64 }
 65 
 66 #endregion
 67 
 68 #region DropDownOnFocus Dependency Property
 69 
 70 /// <summary>
 71 ///     The <see cref="DependencyProperty" /> object of the <see cref="DropDownOnFocus" /> dependency property.
 72 /// </summary>
 73 public static readonly DependencyProperty DropDownOnFocusProperty =
 74 DependencyProperty.Register("DropDownOnFocus", typeof(bool), typeof(AutoFilteredComboBox),
 75 new UIPropertyMetadata(true));
 76 
 77 /// <summary>
 78 ///     Gets or sets the way the combo box behaves when it receives focus.
 79 /// </summary>
 80 /// <value>The way the combo box behaves when it receives focus.</value>
 81 [Description("The way the combo box behaves when it receives focus.")]
 82 [Category("AutoFiltered ComboBox")]
 83 [DefaultValue(true)]
 84 public bool DropDownOnFocus
 85 {
 86 [DebuggerStepThrough]
 87 get { return (bool)GetValue(DropDownOnFocusProperty); }
 88 [DebuggerStepThrough]
 89 set { SetValue(DropDownOnFocusProperty, value); }
 90 }
 91 
 92 #endregion
 93 
 94 #region | Handle selection |
 95 
 96 private int length;
 97 private int start;
 98 
 99 /// <summary>
100 ///     Gets the text box in charge of the editable portion of the combo box.
101 /// </summary>
102 protected TextBox EditableTextBox
103 {
104 get
105 {
106 var txtBox = (TextBox)Template.FindName("PART_EditableTextBox", this);
107 return txtBox;
108 }
109 }
110 
111 public int SecondToFilter { get; set; }
112 
113 /// <summary>
114 ///     Called when <see cref="ComboBox.ApplyTemplate()" /> is called.
115 /// </summary>
116 public override void OnApplyTemplate()
117 {
118 base.OnApplyTemplate();
119 
120 EditableTextBox.SelectionChanged += EditableTextBox_SelectionChanged;
121 }
122 
123 private void EditableTextBox_SelectionChanged(object sender, RoutedEventArgs e)
124 {
125 if (_silenceEvents == 0)
126 {
127 start = ((TextBox)(e.OriginalSource)).SelectionStart;
128 length = ((TextBox)(e.OriginalSource)).SelectionLength;
129 
130 RefreshFilter();
131 }
132 }
133 
134 #endregion
135 
136 #region | Handle focus |
137 
138 /// <summary>
139 ///     Invoked whenever an unhandled <see cref="UIElement.GotFocus" /> event
140 ///     reaches this element in its route.
141 /// </summary>
142 /// <param name="e">The <see cref="RoutedEventArgs" /> that contains the event data.</param>
143 protected override void OnGotFocus(RoutedEventArgs e)
144 {
145 base.OnGotFocus(e);
146 
147 if (ItemsSource != null && DropDownOnFocus)
148 {
149 IsDropDownOpen = true;
150 }
151 }
152 
153 #endregion
154 
155 #region | Handle filtering |
156 
157 private void RefreshFilter()
158 {
159 if (ItemsSource != null)
160 {
161 var view = CollectionViewSource.GetDefaultView(ItemsSource);
162 view.Refresh();
163 IsDropDownOpen = true;
164 }
165 }
166 
167 
168 private bool FilterPredicate(object value)
169 {
170 // We don't like nulls.
171 if (value == null)
172 return false;
173 
174 // If there is no text, there's no reason to filter.
175 if (Text.Length == 0)
176 return true;
177 string thistext = GetTextBySearchPath(value);
178 string prefix = Text;
179 
180 // If the end of the text is selected, do not mind it.
181 if (length > 0 && start + length == Text.Length)
182 {
183 prefix = prefix.Substring(0, start);
184 }
185 if (!IsCaseSensitive)
186 return thistext.IndexOf(prefix, StringComparison.CurrentCultureIgnoreCase) != -1;
187 return thistext.Contains(prefix);
188 }
189 
190 private string GetTextBySearchPath(object value)
191 {
192 var type = value.GetType();
193 var textPath = TextSearch.GetTextPath(this);
194 var propertyInfo = type.GetProperty(textPath);
195 var propertyValue = propertyInfo.GetValue(value);
196 return (string)propertyValue;
197 }
198 
199 #endregion
200 
201 /// <summary>
202 ///     Called when the source of an item in a selector changes.
203 /// </summary>
204 /// <param name="oldValue">Old value of the source.</param>
205 /// <param name="newValue">New value of the source.</param>
206 protected override void OnItemsSourceChanged(IEnumerable oldValue, IEnumerable newValue)
207 {
208 if (newValue != null)
209 {
210 ICollectionView view = CollectionViewSource.GetDefaultView(newValue);
211 view.Filter += FilterPredicate;
212 }
213 
214 if (oldValue != null)
215 {
216 ICollectionView view = CollectionViewSource.GetDefaultView(oldValue);
217 view.Filter -= FilterPredicate;
218 }
219 
220 base.OnItemsSourceChanged(oldValue, newValue);
221 }
222 
223 private void OnTextChanged(object sender, EventArgs e)
224 {
225 if (!IsTextSearchEnabled && _silenceEvents == 0)
226 {
227 RefreshFilter();
228 if (Text.Length > 0)
229 {
230 var collectionView = CollectionViewSource.GetDefaultView(ItemsSource);
231 foreach (object item in collectionView)
232 {
233     int itemlength = item.ToString().Length, prefix = Text.Length;
234     SelectedItem = item;
235 
236     _silenceEvents++;
237     EditableTextBox.Text = item.ToString();
238     EditableTextBox.Select(prefix, itemlength - prefix);
239     _silenceEvents--;
240     break;
241 }
242 }
243 }
244 }
245 }
246 }