public void ListenerChangedIsRaisedWhenDataContextIsReplaced()
{
var myObject = new MyClass {
Value = "Initial"
};
var mySecondObject = new MyClass {
Value = "Final"
};
var binding = new Binding("Value");
var element = new TextBlock {
DataContext = myObject
};
var currentState = string.Empty;
var listener = new DependencyPropertyListener();
listener.Changed += ((s, e) => currentState = (string)e.EventArgs.NewValue);
listener.Attach(element, binding);
var initialState = currentState;
element.DataContext = mySecondObject;
var finalState = currentState;
Assert.AreEqual("Initial", initialState);
Assert.AreEqual("Final", finalState);
}
private void ReturnListener()
{
this.listener.Changed -= this.HandleValueChanged;
BindingListener.freeListeners.Add(this.listener);
this.listener = null;
}
private void Attach() {
this.Detach();
if (this.target != null && this.binding != null) {
this.listener = this.GetListener();
this.listener.Attach(target, binding);
}
}
private void ReturnListener()
{
_listener.Changed -= HandleValueChanged;
_listener.Detach();
FreeListeners.Add(_listener);
_listener = null;
}
private void ReturnListener()
{
this.listener.Changed -= this.HandleValueChanged;
this.listener.Detach();
freeListeners.Add(this.listener);
this.listener = null;
}
private void Attach()
{
this.Detach();
if (this.target != null && this.binding != null)
{
this.listener = this.GetListener();
this.listener.Attach(target, binding);
}
}
private void Attach()
{
Detach();
if (_target != null &&
_binding != null)
{
_listener = GetListener();
_listener.Attach(_target, _binding);
}
}
private static void DisposeInternal(DependencyPropertyListener listener)
{
try
{
if (listener._listener.IsEmpty)
{
return;
}
listener.ClearValue(ValueProperty);
listener._listener = WeakEventListenerWrapper.Empty;
}
catch (InvalidOperationException e)
{
Tracer.Error(e.Flatten(true));
}
}
private DependencyPropertyListener GetListener()
{
DependencyPropertyListener listener;
if (FreeListeners.Count != 0)
{
listener = FreeListeners[FreeListeners.Count - 1];
FreeListeners.RemoveAt(FreeListeners.Count - 1);
return(listener);
}
listener = new DependencyPropertyListener();
listener.Changed += HandleValueChanged;
return(listener);
}
public void TracksChanges()
{
var changes = new List <DependencyPropertyChangedEventArgs>();
var textBlock = new TextBlock();
var listener = new DependencyPropertyListener(textBlock, TextBlock.TextProperty);
listener.Changed += (_, e) => changes.Add(e);
textBlock.Text = "1";
Assert.AreEqual(1, changes.Count);
Assert.AreEqual(string.Empty, changes.Last().OldValue);
Assert.AreEqual("1", changes.Last().NewValue);
textBlock.Text = "2";
Assert.AreEqual(2, changes.Count);
Assert.AreEqual("1", changes.Last().OldValue);
Assert.AreEqual("2", changes.Last().NewValue);
listener.Dispose();
}
private DependencyPropertyListener GetListener()
{
DependencyPropertyListener listener;
if (freeListeners.Count != 0)
{
listener = freeListeners[freeListeners.Count - 1];
freeListeners.RemoveAt(freeListeners.Count - 1);
return(listener);
}
else
{
listener = new DependencyPropertyListener();
}
listener.Changed += this.HandleValueChanged;
return(listener);
}
public TSource TryUpdateSubscription(BindingMode bindingMode, TSource source)
{
if (DataBindingHelper.RequiresSourcePropertyChangeNotification(bindingMode))
{
var newSource = this.sourceContext.Source;
if (!Equals(newSource, source))
{
this.Unsubscribe(source);
source = newSource;
if (!Equals(source, default))
{
if (source is DependencyObject dependencyObject)
{
this.dependencyPropertyListener = DependencyPropertyListener.Subscribe(dependencyObject, this.DependencyProperty, this.OnDataContextInvalidateRequired);
}
}
}
}
return(source);
}
private void Attach()
{
Detach();
if (_target != null
&& _binding != null)
{
_listener = GetListener();
_listener.Attach(_target, _binding);
}
}
private void ReturnListener()
{
this.listener.Changed -= this.HandleValueChanged;
freeListeners.Add(this.listener);
this.listener = null;
}
private DependencyPropertyListener GetListener()
{
DependencyPropertyListener listener;
if (freeListeners.Count != 0)
{
listener = freeListeners[freeListeners.Count - 1];
freeListeners.RemoveAt(freeListeners.Count - 1);
return listener;
}
listener = new DependencyPropertyListener();
listener.Changed += this.HandleValueChanged;
return listener;
}
private DependencyPropertyListener GetListener()
{
DependencyPropertyListener listener;
if (BindingListener.freeListeners.Count != 0) {
listener = BindingListener.freeListeners[BindingListener.freeListeners.Count - 1];
BindingListener.freeListeners.RemoveAt(BindingListener.freeListeners.Count - 1);
return listener;
}
else
listener = new DependencyPropertyListener();
listener.Changed += this.HandleValueChanged;
return listener;
}
public void Unsubscribe(TSource source)
{
this.dependencyPropertyListener?.Dispose();
this.dependencyPropertyListener = null;
}
private void ReturnListener()
{
_listener.Changed -= HandleValueChanged;
_listener.Detach();
FreeListeners.Add(_listener);
_listener = null;
}
