C# DependencyProperty未在NotifyCollectionChanged事件上通知UI
我正在使用一个自定义控件,该控件具有selected items dependency属性,我已将该属性连接到collection changed事件,但未通知UI,并且PropertyChanged事件始终为null。通常我会说这是一个datacontext问题。但我无法更改控件上的数据上下文,因为不会显示任何数据C# DependencyProperty未在NotifyCollectionChanged事件上通知UI,c#,wpf,xaml,silverlight-5.0,C#,Wpf,Xaml,Silverlight 5.0,我正在使用一个自定义控件,该控件具有selected items dependency属性,我已将该属性连接到collection changed事件,但未通知UI,并且PropertyChanged事件始终为null。通常我会说这是一个datacontext问题。但我无法更改控件上的数据上下文,因为不会显示任何数据 public ObservableCollection<object> SelectedItems { get { return (Ob
public ObservableCollection<object> SelectedItems
{
get { return (ObservableCollection<object>)GetValue(SelectedItemsProperty); }
set { SetValue(SelectedItemsProperty, value); }
}
// Using a DependencyProperty as the backing store for SelectedItems. This enables animation, styling, binding, etc...
public static readonly DependencyProperty SelectedItemsProperty =
DependencyProperty.RegisterAttached("SelectedItems", typeof(ObservableCollection<object>),
typeof(MultiSelectComboBox),
new System.Windows.PropertyMetadata(new ObservableCollection<object>(), new PropertyChangedCallback(SelectedItemsPropertyChanged)));
private static void SelectedItemsPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
MultiSelectComboBox relay = d as MultiSelectComboBox;
if (e.OldValue != null)
{
var coll = (INotifyCollectionChanged)e.OldValue;
coll.CollectionChanged -= relay.SelectedItemsCollectionChanged;
}
if (e.NewValue != null)
{
var coll = (INotifyCollectionChanged)e.NewValue;
coll.CollectionChanged += relay.SelectedItemsCollectionChanged;
}
}
public observateCollection SelectedItems
{
get{return(ObservableCollection)GetValue(SelectedItemsProperty);}
set{SetValue(selecteditemsprroperty,value);}
}
//使用DependencyProperty作为SelectedItems的备份存储。这将启用动画、样式、绑定等。。。
公共静态只读从属属性SelectedItemsProperty=
DependencyProperty.RegisterAttached(“SelectedItems”,类型为(ObservableCollection),
类型(多选组合框),
新建System.Windows.PropertyMetadata(新建ObservableCollection(),新建PropertyChangedCallback(SelectedItemsPropertyChanged));
私有静态void SelectedItemsPropertyChanged(DependencyObject d,DependencyPropertyChangedEventArgs e)
{
MultiSelectComboBox继电器=d作为MultiSelectComboBox;
如果(e.OldValue!=null)
{
var coll=(INotifyCollectionChanged)e.OldValue;
coll.CollectionChanged-=relay.selecteditemscolectionchanged;
}
如果(如NewValue!=null)
{
var coll=(INotifyCollectionChanged)e.NewValue;
coll.CollectionChanged+=relay.selecteditemscolectionchanged;
}
}
上面是属性声明,它在xaml中绑定到ViewModel上的ObservableCollection。我错过了什么。该控件实现INotifyPropertyChanged
我在下面添加了更多代码。这是原始代码,我想将相同的属性更改为用于绑定到集合pupose的依赖属性
namespace Kepler.SilverlightControls.MultiSelectComboBox
{
/// <summary>
/// MultiSelect ComboBox
/// </summary>
public class MultiSelectComboBox : Telerik.Windows.Controls.RadComboBox, INotifyPropertyChanged
{
#region Events
/// <summary>
/// Est appelé quand une propriété change
/// </summary>
public event PropertyChangedEventHandler PropertyChanged;
#endregion
#region Constructor
/// <summary>
/// Initializes a new instance of MultiSelectComboBox
/// </summary>
public MultiSelectComboBox()
{
ClearSelectionButtonVisibility = Visibility.Collapsed;
string xaml = @"<DataTemplate
xmlns=""http://schemas.microsoft.com/winfx/2006/xaml/presentation""
xmlns:x=""http://schemas.microsoft.com/winfx/2006/xaml""
xmlns:local=""clr-namespace:Kepler.SilverlightControls.MultiSelectComboBox;assembly=Kepler.SilverlightControls"">
<TextBlock TextWrapping=""Wrap"" local:MultiSelectComboBoxService.SelectionBoxLoaded=""True"" />
</DataTemplate>";
var selectionBoxTemplate = (DataTemplate)XamlReader.Load(xaml);
SelectionBoxTemplate = selectionBoxTemplate;
EmptySelectionBoxTemplate = selectionBoxTemplate;
xaml = @"<DataTemplate
xmlns=""http://schemas.microsoft.com/winfx/2006/xaml/presentation""
xmlns:x=""http://schemas.microsoft.com/winfx/2006/xaml""
xmlns:local=""clr-namespace:Kepler.SilverlightControls.MultiSelectComboBox;assembly=Kepler.SilverlightControls"">
<CheckBox local:MultiSelectComboBoxService.ComboBoxItemLoaded=""True""
IsChecked=""{Binding Path=(local:MultiSelectComboBoxService.IsChecked), Mode=TwoWay, RelativeSource={RelativeSource Self}}"" />
</DataTemplate>";
ItemTemplate = (DataTemplate)XamlReader.Load(xaml);
}
#endregion
#region Propriétés
/// <summary>
/// IsCheckedBindingPath Property
/// </summary>
public string IsCheckedBindingPath
{
get { return (string)GetValue(IsCheckedBindingPathProperty); }
set { SetValue(IsCheckedBindingPathProperty, value); }
}
// Using a DependencyProperty as the backing store for IsCheckedBindingPath. This enables animation, styling, binding, etc...
public static readonly DependencyProperty IsCheckedBindingPathProperty =
DependencyProperty.Register("IsCheckedBindingPath", typeof(string), typeof(MultiSelectComboBox), new PropertyMetadata(null, (obj, e) =>
{
Telerik.Windows.Controls.TextSearch.SetTextPath(obj, e.NewValue as string);
}));
/// <summary>
/// DisplayBindingPath Property
/// </summary>
public static readonly DependencyProperty DisplayBindingPathProperty = DependencyProperty.Register(
"DisplayBindingPath", typeof(string), typeof(MultiSelectComboBox), new PropertyMetadata(null, (obj, e) =>
{
Telerik.Windows.Controls.TextSearch.SetTextPath(obj, e.NewValue as string);
}));
/// <summary>
/// Gets or sets the display member path (we can't reuse DisplayMemberPath property)
/// </summary>
public string DisplayBindingPath
{
get { return GetValue(DisplayBindingPathProperty) as string; }
set { SetValue(DisplayBindingPathProperty, value); }
}
private ObservableCollection<object> _selectedItems;
/// <summary>
/// Gets the selected items
/// </summary>
public ObservableCollection<object> SelectedItems
{
get
{
if (_selectedItems == null)
{
_selectedItems = new ObservableCollection<object>();
_selectedItems.CollectionChanged += new NotifyCollectionChangedEventHandler(SelectedItemsCollectionChanged);
}
return _selectedItems;
}
}
private ObservableCollection<object> _selectedValues;
/// <summary>
/// Gets the selected values
/// </summary>
public ObservableCollection<object> SelectedValues
{
get
{
if (_selectedValues == null)
{
_selectedValues = new ObservableCollection<object>();
_selectedValues.CollectionChanged += new NotifyCollectionChangedEventHandler(SelectedValuesCollectionChanged);
}
return _selectedValues;
}
}
#endregion
#region Methods
/// <summary>
/// Called when the Items property changed
/// </summary>
/// <param name="e">change informations</param>
protected override void OnItemsChanged(NotifyCollectionChangedEventArgs e)
{
base.OnItemsChanged(e);
int idx;
var selectedItems = SelectedItems;
switch (e.Action)
{
case NotifyCollectionChangedAction.Add:
case NotifyCollectionChangedAction.Replace:
case NotifyCollectionChangedAction.Reset:
var items = e.NewItems;
if (items == null)
{
var selected = new List<object>();
foreach (var item in this.ItemsSource)
{
PropertyInfo isCheckedBindingPathProperty = this.IsCheckedBindingPath != null ? item.GetType().GetProperty(this.IsCheckedBindingPath) : null;
if (isCheckedBindingPathProperty != null
&& (bool)isCheckedBindingPathProperty.GetValue(item,null) == true)
{
selected.Add(item);
SelectedValues.Add(item.GetType().GetProperty(SelectedValuePath).GetValue(item, null));
}
}
items = selected;
}
if (items != null)
{
foreach (object value in SelectedValues)
{
foreach (object item in items)
{
if (GetSelectedValue(item).Equals(value) && !selectedItems.Contains(item))
{
selectedItems.Add(item);
}
}
}
}
break;
case NotifyCollectionChangedAction.Remove:
foreach (object item in e.OldItems)
{
idx = selectedItems.IndexOf(item);
if (idx >= 0)
{
selectedItems.RemoveAt(idx);
}
}
break;
}
}
private void RemoveCollectionChangedEvents()
{
SelectedItems.CollectionChanged -= new NotifyCollectionChangedEventHandler(SelectedItemsCollectionChanged);
SelectedValues.CollectionChanged -= new NotifyCollectionChangedEventHandler(SelectedValuesCollectionChanged);
}
private void AddCollectionChangedEvents()
{
SelectedItems.CollectionChanged += new NotifyCollectionChangedEventHandler(SelectedItemsCollectionChanged);
SelectedValues.CollectionChanged += new NotifyCollectionChangedEventHandler(SelectedValuesCollectionChanged);
}
private void SelectedItemsCollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
{
if (SelectedValuePath != null)
{
RemoveCollectionChangedEvents();
try
{
switch (e.Action)
{
case NotifyCollectionChangedAction.Add:
AddSelectedValues(e.NewItems);
break;
case NotifyCollectionChangedAction.Remove:
RemoveSelectedValues(e.OldItems);
break;
case NotifyCollectionChangedAction.Replace:
RemoveSelectedValues(e.OldItems);
AddSelectedValues(e.NewItems);
break;
case NotifyCollectionChangedAction.Reset:
SelectedValues.Clear();
foreach (object item in Items)
{
UpdateSelectedItem(item, false);
}
AddSelectedValues(e.NewItems);
break;
}
}
finally
{
AddCollectionChangedEvents();
}
}
RaiseSelectedItemsPropertyChanged();
}
private void RemoveSelectedValues(IList items)
{
foreach (var item in items)
{
SelectedValues.Remove(GetSelectedValue(item));
UpdateSelectedItem(item, false);
}
}
private void AddSelectedValues(IList items)
{
if (items != null)
{
object selectedValue;
foreach (var item in items)
{
selectedValue = GetSelectedValue(item);
if (!SelectedValues.Contains(selectedValue))
{
SelectedValues.Add(selectedValue);
}
UpdateSelectedItem(item, true);
}
}
}
private object GetSelectedValue(object item)
{
return DataControlHelper.GetPropertyInfo(item.GetType(), SelectedValuePath).GetValue(item, null);
}
private void SelectedValuesCollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
{
RemoveCollectionChangedEvents();
try
{
switch (e.Action)
{
case NotifyCollectionChangedAction.Add:
AddSelectedItems(e.NewItems);
break;
case NotifyCollectionChangedAction.Remove:
RemoveSelectedItems(e.OldItems);
break;
case NotifyCollectionChangedAction.Replace:
RemoveSelectedItems(e.OldItems);
AddSelectedItems(e.NewItems);
break;
case NotifyCollectionChangedAction.Reset:
var selectedItems = SelectedItems.ToList();
SelectedItems.Clear();
foreach (object item in selectedItems)
{
UpdateSelectedItem(item, false);
}
AddSelectedItems(e.NewItems);
break;
}
}
finally
{
AddCollectionChangedEvents();
}
RaiseSelectedItemsPropertyChanged();
}
private void RaiseSelectedItemsPropertyChanged()
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs("SelectedItems"));
// To update the selection box
}
}
private void RemoveSelectedItems(IList values)
{
object item;
foreach (var value in values)
{
item = SelectedItems.FirstOrDefault(e => GetSelectedValue(e).Equals(value));
if (item != null)
{
SelectedItems.Remove(item);
UpdateSelectedItem(item, false);
}
}
}
private void AddSelectedItems(IList values)
{
if (values != null)
{
object item;
foreach (var value in values)
{
item = Items.FirstOrDefault(e => GetSelectedValue(e).Equals(value));
if (item != null)
{
SelectedItems.Add(item);
UpdateSelectedItem(item, true);
}
}
}
}
private void UpdateSelectedItem(object item, bool select)
{
var obj = ItemContainerGenerator.ContainerFromItem(item);
if (obj != null)
{
var cb = obj.FindChildByType<CheckBox>();
if (cb != null && cb.IsChecked != select)
{
cb.IsChecked = select;
}
}
}
/// <summary>
/// Create a new ComboBox item
/// </summary>
/// <returns>a new ComboBox item</returns>
protected override DependencyObject GetContainerForItemOverride()
{
return new MultiSelectComboBoxItem(this);
}
protected override void OnKeyDown(System.Windows.Input.KeyEventArgs e)
{
base.OnKeyDown(e);
IsDropDownOpen = true;
}
#endregion
}
namespace Kepler.SilverlightControls.MultiSelectComboBox
{
///
///多选组合框
///
公共类MultiSelectComboBox:Telerik.Windows.Controls.RadComboBox,INotifyPropertyChanged
{
#地区活动
///
///这是一种自然的变化
///
公共事件属性更改事件处理程序属性更改;
#端区
#区域构造函数
///
///初始化MultiSelectComboBox的新实例
///
公共多选组合框()
{
ClearSelectionButtonVisibility=可见性。已折叠;
字符串xaml=@”
";
var selectionBoxTemplate=(DataTemplate)XamlReader.Load(xaml);
SelectionBoxTemplate=SelectionBoxTemplate;
EmptySelectionBoxTemplate=selectionBoxTemplate;
xaml=@”
";
ItemTemplate=(DataTemplate)XamlReader.Load(xaml);
}
#端区
#固有区域
///
///IsCheckedBindingPath属性
///
公共字符串IsCheckedBindingPath
{
get{return(string)GetValue(IsCheckedBindingPathProperty);}
set{SetValue(IsCheckedBindingPathProperty,value);}
}
//使用DependencyProperty作为IsCheckedBindingPath的备份存储。这将启用动画、样式、绑定等。。。
公共静态只读从属属性IsCheckedBindingPathProperty=
DependencyProperty.Register(“IsCheckedBindingPath”、typeof(string)、typeof(MultiSelectComboBox)、new PropertyMetadata(null,(obj,e)=>
{
Telerik.Windows.Controls.TextSearch.SetTextPath(obj,e.NewValue作为字符串);
}));
///
///DisplayBindingPath属性
///
公共静态只读DependencyProperty DisplayBindingPathProperty=DependencyProperty.Register(
“DisplayBindingPath”、typeof(字符串)、typeof(MultiSelectComboBox)、新PropertyMetadata(null,(obj,e)=>
{
Telerik.Windows.Controls.TextSearch.SetTextPath(obj,e.NewValue作为字符串);
}));
///
///获取或设置显示成员路径(无法重用DisplayMemberPath属性)
///
公共字符串显示绑定路径
{
获取{返回GetValue(DisplayBindingPathProperty)作为字符串;}
set{SetValue(DisplayBindingPathProperty,value);}
}
私有可观测集合_selectedItems;
///
///获取所选项目
///
公共可观测集合SelectedItems
{
得到
{
如果(_selectedItems==null)
{
_selectedItems=新的ObservableCollection();
_selectedItems.CollectionChanged+=new NotifyCollectionChangedEventHandler(SelectedItemsCollectionChanged);
}
返回_selectedItems;
}
}
私有可观察集合_选择的值;
///
///获取选定的值
///
公共可观察集合SelectedValues
{
得到
{
如果(_selectedValues==null)
{
_selectedValues=新的ObservableCollection();
_selectedValues.CollectionChanged+=新的NotifyCollectionChangedEventHandler(SelectedValuesCollectionChanged);
}
返回所选的值;
}
}
#端区
#区域方法
///
///在Items属性更改时调用
///
///更改信息
已更改受保护的覆盖(NotifyCollectionChangedEventArgs e)
{
碱基(e);
int-idx;
var selectedItems=selectedItems;
开关(电动)
{
案例NotifyCollectionChangedAction。添加:
案例通知收集更改操作。替换:
案例通知CollectionChangedAction.Reset:
var项目=e.NewItems;
if(items==null)
{
所选变量=新列表();
foreach(此.ItemsSource中的var项)
{
namespace Kepler.SilverlightControls.MultiSelectComboBox
{
/// <summary>
/// Service for the MultiSelect comboBox
/// </summary>
public static class MultiSelectComboBoxService
{
/// <summary>
/// IsChecked property
/// </summary>
public static DependencyProperty IsCheckedProperty = DependencyProperty.RegisterAttached("IsChecked",
typeof(bool), typeof(MultiSelectComboBoxService), new PropertyMetadata(false, (obj, e) =>
{
MultiSelectComboBoxItem comboBoxItem = obj.GetVisualParent<MultiSelectComboBoxItem>();
if (comboBoxItem != null)
{
MultiSelectComboBox comboBox = comboBoxItem.ParentComboBox;
var selectedItems = (IList)comboBox.SelectedItems;
object item = comboBoxItem.DataContext;
PropertyInfo isCheckedBindingPathProperty = item.GetType().GetProperty(comboBox.IsCheckedBindingPath);
isCheckedBindingPathProperty.SetValue(item, e.NewValue,null);
if ((bool)e.NewValue)
{
if (!selectedItems.Contains(item))
{
selectedItems.Add(item);
}
}
else
{
selectedItems.Remove(item);
}
}
}));
/// <summary>
/// Gets a value indicating if the object is checked or not
/// </summary>
/// <param name="obj">DependencyObject</param>
/// <returns>a value indicating if the object is checked or not</returns>
public static bool GetIsChecked(DependencyObject obj)
{
return (bool)obj.GetValue(IsCheckedProperty);
}
/// <summary>
/// Sets a value indicating if the object is checked or not
/// </summary>
/// <param name="obj">DependencyObject</param>
/// <param name="value">the value indicating if the object is checked or not</param>
public static void SetIsChecked(DependencyObject obj, bool value)
{
obj.SetValue(IsCheckedProperty, value);
}
/// <summary>
/// SelectionBoxLoaded property called on SelectionBox load
/// </summary>
public static DependencyProperty SelectionBoxLoadedProperty = DependencyProperty.RegisterAttached("SelectionBoxLoaded",
typeof(bool), typeof(MultiSelectComboBoxService), new PropertyMetadata(false, (obj, e) =>
{
TextBlock targetElement = obj as TextBlock;
if (targetElement != null)
{
targetElement.Loaded += new RoutedEventHandler(targetElement_Loaded);
}
}));
private static void targetElement_Loaded(object sender, RoutedEventArgs e)
{
TextBlock targetElement = (TextBlock)sender;
targetElement.Loaded -= new RoutedEventHandler(targetElement_Loaded);
MultiSelectComboBox comboBox = targetElement.GetVisualParent<MultiSelectComboBox>();
if (comboBox != null)
{
targetElement.SetBinding(TextBlock.TextProperty, new Binding("SelectedItems")
{
Converter = new MultiSelectComboxConverter(),
Source = comboBox,
ConverterParameter = comboBox.DisplayBindingPath
});
}
}
/// <summary>
/// Gets the value indicating if the object is loaded or not
/// </summary>
/// <param name="obj">DependencyObject</param>
/// <returns>the value indicating if the object is loaded or not</returns>
public static bool GetSelectionBoxLoaded(DependencyObject obj)
{
return (bool)obj.GetValue(SelectionBoxLoadedProperty);
}
/// <summary>
/// Sets the value indicating if the object is loaded or not
/// </summary>
/// <param name="obj">DependencyObject</param>
/// <param name="value">the value indicating if the object is loaded or not</param>
public static void SetSelectionBoxLoaded(DependencyObject obj, bool value)
{
obj.SetValue(SelectionBoxLoadedProperty, value);
}
/// <summary>
/// ComboBoxItemLoaded called on ComboBoxItem load
/// </summary>
public static DependencyProperty ComboBoxItemLoadedProperty = DependencyProperty.RegisterAttached("ComboBoxItemLoaded",
typeof(bool), typeof(MultiSelectComboBoxService), new PropertyMetadata(false, (obj, e) =>
{
CheckBox targetElement = obj as CheckBox;
if (targetElement != null)
{
targetElement.Loaded += new RoutedEventHandler(comboBoxItem_Loaded);
targetElement.SetBinding(MultiSelectComboBoxService.DataContextProperty, new Binding());
}
}));
private static void comboBoxItem_Loaded(object sender, RoutedEventArgs e)
{
FrameworkElement element = (FrameworkElement)sender;
MultiSelectComboBox comboBox = GetComboBox(element);
if (comboBox != null)
{
element.SetBinding(CheckBox.ContentProperty, new Binding(comboBox.DisplayBindingPath));
//Binding binding = new Binding(comboBox.IsCheckedBindingPath);
//binding.Mode = BindingMode.TwoWay;
//element.SetBinding(CheckBox.IsCheckedProperty, binding);
}
}
/// <summary>
///Gets the value indicating if the item is loaded or not
/// </summary>
/// <param name="obj">DependencyObject</param>
/// <returns>the value indicating if the item is loaded or not</returns>
public static bool GetComboBoxItemLoaded(DependencyObject obj)
{
return (bool)obj.GetValue(ComboBoxItemLoadedProperty);
}
/// <summary>
/// Sets the value indicating if the item is loaded or not
/// </summary>
/// <param name="obj">DependencyObject</param>
/// <param name="value">the value indicating if the item is loaded or not</param>
public static void SetComboBoxItemLoaded(DependencyObject obj, bool value)
{
obj.SetValue(ComboBoxItemLoadedProperty, value);
}
private static MultiSelectComboBox GetComboBox(DependencyObject targetElement)
{
MultiSelectComboBoxItem item = targetElement.GetVisualParent<MultiSelectComboBoxItem>();
if (item != null)
{
return item.ParentComboBox;
}
return null;
}
private static DependencyProperty DataContextProperty = DependencyProperty.RegisterAttached("DataContext",
typeof(object), typeof(MultiSelectComboBoxService), new PropertyMetadata(null, (obj, e) =>
{
CheckBox checkBox = (CheckBox)obj;
MultiSelectComboBox comboBox = GetComboBox(checkBox);
if (comboBox != null)
{
checkBox.IsChecked = comboBox.SelectedItems.Contains(checkBox.DataContext);
}
}));
private static object GetDataContext(DependencyObject obj)
{
return obj.GetValue(DataContextProperty);
}
private static void SetDataContext(DependencyObject obj, object value)
{
obj.SetValue(DataContextProperty, value);
}
}
namespace Kepler.SilverlightControls.MultiSelectComboBox
{
#region Méthodes
public class MultiSelectComboxConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
{
string displayMemberPath = parameter as string;
if (String.IsNullOrWhiteSpace(displayMemberPath))
{
return String.Empty;
}
PropertyInfo propertyInfo;
return string.Join(", ", (value as IEnumerable<object>).Select(item =>
{
propertyInfo = DataControlHelper.GetPropertyInfo(item.GetType(), displayMemberPath);
if (propertyInfo == null)
{
return String.Empty;
}
return propertyInfo.GetValue(item, null);
}).ToArray());
}
/// <summary>
/// Not implemented
/// </summary>
public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
{
throw new NotImplementedException();
}
#endregion
}
public static readonly DependencyProperty SelectedItemsProperty =
DependencyProperty.Register( // Register instead of RegisterAttached
"SelectedItems",
typeof(ObservableCollection<object>),
typeof(MultiSelectComboBox),
new PropertyMetadata(SelectedItemsPropertyChanged)); // no default value
public static readonly DependencyProperty SelectedItemsProperty =
DependencyProperty.Register(
"SelectedItems",
typeof(ICollection),
typeof(MultiSelectComboBox),
new PropertyMetadata(SelectedItemsPropertyChanged));
public ICollection SelectedItems
{
get { return (ICollection)GetValue(SelectedItemsProperty); }
set { SetValue(SelectedItemsProperty, value); }
}
private static void SelectedItemsPropertyChanged(
DependencyObject obj, DependencyPropertyChangedEventArgs e)
{
var comboBox = (MultiSelectComboBox)obj;
var oldCollection = e.OldValue as INotifyCollectionChanged;
var newCollection = e.NewValue as INotifyCollectionChanged;
if (oldCollection != null)
{
oldCollection.CollectionChanged -= SelectedItemsCollectionChanged;
}
if (newCollection != null)
{
newCollection.CollectionChanged += SelectedItemsCollectionChanged;
}
}
private static void SelectedItemsCollectionChanged(
object sender, NotifyCollectionChangedEventArgs e)
{
switch (e.Action)
{
...
}
}