我有一个基本的DependencyObject类，其中我有一个获取对象的方法，获取属性，并且对于实现INotifyPropertyChanged的类型的每个属性，我添加了一个新的PropertyChangedEventHandler。现在在处理程序方法中，它获取对象“sender”和PropertyChangedEventArgs“e”的参数。我的问题是，如果sender是实现INotifyPropertyChanged的类型的属性，有没有人知道如何动态获取属性名称。
以下是我正在使用的内容：
public class BaseDependencyObject : DependencyObject, INotifyPropertyChanged
{
public BaseDependencyObject()
{
}
protected void SetValues(Object thisObject, Object entity)
{
try
{
PropertyInfo[] properties = entity.GetType().GetProperties();
foreach (PropertyInfo property in properties)
{
var value = property.GetValue(entity, null);
var valueIsEntity = value is System.ServiceModel.DomainServices.Client.Entity;
var thisObjectsProperty = thisObject.GetType().GetProperty(property.Name);
if (thisObjectsProperty != null && value != null)
{
if (valueIsEntity)
{
if (thisObjectsProperty.PropertyType.GetInterface("INotifyPropertyChanged", true) != null)
{
var propertyInstance = Activator.CreateInstance(thisObjectsProperty.PropertyType);
((INotifyPropertyChanged)propertyInstance).PropertyChanged += new PropertyChangedEventHandler(Object_PropertyChanged);
}
SetValues(thisObjectsProperty, value);
}
else if (thisObjectsProperty.PropertyType.GetInterface("ICollection", true) != null
&& thisObjectsProperty.PropertyType.GetGenericArguments().Count() > 0)
{
Type genericType = thisObjectsProperty.PropertyType.GetGenericArguments()[0];
var observableCollection = Activator.CreateInstance(thisObjectsProperty.PropertyType) as IList;
if (observableCollection is INotifyCollectionChanged)
((INotifyCollectionChanged)observableCollection).CollectionChanged += this.Object_CollectionChanged;
if (observableCollection is INotifyPropertyChanged)
((INotifyPropertyChanged)observableCollection).PropertyChanged += new PropertyChangedEventHandler(Object_PropertyChanged);
foreach (var item in (IEnumerable)value)
{
var newItem = Activator.CreateInstance(genericType);
if (newItem != null)
{
SetValues(newItem, item);
observableCollection.Add(newItem);
}
}
}
else
{
thisObjectsProperty.SetValue(thisObject, value, null);
}
}
}
}
catch (Exception ex)
{
throw ex;
}
}
protected void Object_CollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
{
switch (e.Action)
{
case NotifyCollectionChangedAction.Add:
foreach (var item in e.NewItems)
{
if (item is INotifyPropertyChanged)
{
((INotifyPropertyChanged)item).PropertyChanged += new PropertyChangedEventHandler(Object_PropertyChanged);
}
}
break;
case NotifyCollectionChangedAction.Remove:
foreach (var item in e.OldItems)
{
if (item is INotifyPropertyChanged)
{
((INotifyPropertyChanged)item).PropertyChanged -= this.Object_PropertyChanged;
}
}
break;
}
}
protected void Object_PropertyChanged(object sender, PropertyChangedEventArgs e)
{
this.NotifyPropertyChanged(e.PropertyName);
}
public event PropertyChangedEventHandler PropertyChanged;
protected void NotifyPropertyChanged(string propertyName)
{
var handler = PropertyChanged;
if (handler != null)
handler(this, new PropertyChangedEventArgs(propertyName));
}
}
SetValues方法的第一个参数是将在视图模型中使用的DependencyObject类型。第二个参数是从DomainService的Context.LoadOperation返回的实体。
我的问题归结为当INotifyCollectionChanged.CollectionChanged触发时我需要能够使用集合的属性名称引发PropertyChanged事件。所以如果有人有任何建议我会非常感激。提前谢谢。
修改
弄清楚如何获取触发事件的属性名称。这是我的PropertyChangedEventHandler的编辑版本。
protected void Object_PropertyChanged(object sender, PropertyChangedEventArgs e)
{
var properties = this.GetType().GetProperties().Where(x => x.PropertyType == sender.GetType()).ToArray();
foreach (var property in properties)
{
this.NotifyPropertyChanged(property.Name);
}
//this.NotifyPropertyChanged(e.PropertyName);
}
基本上这就是我所寻找的，但是我仍然没有做正确的事情。当添加作为另一种类型的属性的ObservableCollection时，UIElement仍未更新。
以下是我的DependencyObjects和ViewModel的示例：
public class LOB : DependencyObject
{
public Int32 ID
{
get { return (Int32)GetValue(IDProperty); }
set
{
SetValue(IDProperty, value);
NotifyPropertyChanged("ID");
}
}
public static readonly DependencyProperty IDProperty =
DependencyProperty.Register("ID", typeof(Int32), typeof(LOB), null);
public ObservableCollection<Group> Groups
{
get { return (ObservableCollection<Group>)GetValue(GroupsProperty); }
set
{
SetValue(GroupsProperty, value);
NotifyPropertyChanged("Groups");
}
}
public static readonly DependencyProperty GroupsProperty =
DependencyProperty.Register("Groups", typeof(ObservableCollection<Group>), typeof(LOB), new PropertyMetadata(null, OnGroupsPropertyChanged));
static void OnGroupsPropertyChanged(DependencyObject obj, DependencyPropertyChangedEventArgs e)
{
if (e.NewValue != null)
{
((INotifyCollectionChanged)e.NewValue).CollectionChanged += new NotifyCollectionChangedEventHandler(((LOB)obj).Object_CollectionChanged);
((INotifyPropertyChanged)e.NewValue).PropertyChanged += new PropertyChangedEventHandler(((LOB)obj).Object_PropertyChanged);
}
if (e.OldValue != null)
{
((INotifyCollectionChanged)e.OldValue).CollectionChanged -= ((LOB)obj).Object_CollectionChanged;
((INotifyPropertyChanged)e.OldValue).PropertyChanged -= ((LOB)obj).Object_PropertyChanged;
}
}
}
public class Group : DependencyObject
{
public Int32 ID
{
get { return (Int32)GetValue(IDProperty); }
set
{
SetValue(IDProperty, value);
NotifyPropertyChanged("ID");
}
}
public static readonly DependencyProperty IDProperty =
DependencyProperty.Register("ID", typeof(Int32), typeof(Group), null);
public String GroupName
{
get { return (String)GetValue(GroupNameProperty); }
set
{
SetValue(GroupNameProperty, value);
NotifyPropertyChanged("GroupName");
}
}
public static readonly DependencyProperty GroupNameProperty =
DependencyProperty.Register("GroupName", typeof(String), typeof(Group), null);
}
public class MyViewModel : DependencyObject
{
public static readonly DependencyProperty LobCollectionProperty =
DependencyProperty.Register("LobCollection",
typeof(ObservableCollection<LOB>),
typeof(MyViewModel),
new PropertyMetadata(null, LobCollectionPropertyChanged));
public ObservableCollection<LOB> LobCollection
{
get { return (ObservableCollection<MainBusinessLine>)GetValue(LobCollectionPropertyChanged); }
set
{
SetValue(MainBusinessLineCollectionProperty, value);
NotifyPropertyChanged("LobCollection");
}
}
static void LobCollectionPropertyChanged(DependencyObject obj, DependencyPropertyChangedEventArgs e)
{
var viewModel = obj as MyViewModel;
if (viewModel == null)
return;
if (e.OldValue != null)
{
((INotifyCollectionChanged)e.OldValue).CollectionChanged -= viewModel.LobCollection_Changed;
}
if (e.NewValue != null)
{
((INotifyCollectionChanged)e.NewValue).CollectionChanged += viewModel.LobCollection_Changed;
}
}
void LobCollection_Changed(object sender, NotifyCollectionChangedEventArgs e)
{
NotifyPropertyChanged("LobCollection");
}
}
答案 0 :(得分：2)
在我们上面的讨论之后，这是没有实际意义的，但我想到了当一个集合在由子类定义的属性中发生更改时，我如何实现一个触发PropertyChanged事件的基类。正如我所说，它有点不标准，但这就是我要做的。
class FancyCollectionAndPropertyChangedBase : INotifyPropertyChanged
{
private Dictionary<ICollectionChanged, String> collectionNameLookup = new Dictionary<ICollectionChanged, String>();
protected FancyCollectionAndPropertyChangedBase()
{
this.PropertyChanged += MyPropertyChanged;
}
private void MyPropertyChanged(object sender, PropertyChangedEventArgs e)
{
if(this.collectionNameLookup.ContainsValue(e.PropertyName)
{
KeyValuePair<INotifyCollectionChanged, String> oldValue = this.collectionNameLookup.First(kvp => kvp.Value == e.Name);
oldValue.Key -= MyCollectionChanged;
this.collecitonNameLookup.Remove(oldValue.Key);
INotifyCollectionChanged collection = this.GetType().GetProperty(e.PropertyName, BindingFlags.FlattenHierarchy).GetValue(this, null);
collection.CollectionChanged += MyCollectionChanged;
this.collectionNameLookup.Add(collection, e.Name);
}
else if(typeof(INotifyCollectionChanged).IsAssignableFrom(this.GetType().GetProperty(e.PropertyName, BindingFlags.FlattenHierarchy).PropertyType))
{
// Note: I may have gotten the IsAssignableFrom statement, above, backwards.
INotifyCollectionChanged collection = this.GetType().GetProperty(e.PropertyName, BindingFlags.FlattenHierarchy).GetValue(this, null);
collection.CollectionChanged += MyCollectionChanged;
this.collectionNameLookup.Add(collection, e.Name);
}
}
private void MyCollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
{
this.NotifyPropertyChanged(this.collectionNameLookup[sender];
}
}