private void ObserveProperty(PropertyInfo propertyInfo, EventHandler <ObservablePropertyChangedEventArgs> handler)
{
ObservedProperty observedProperty;
if (!_observedProperties.TryGetValue(propertyInfo.Name, out observedProperty))
{
observedProperty = new ObservedProperty(propertyInfo);
observedProperty.CurrentValue = propertyInfo.GetValue(this, null);
observedProperty.Handlers = new EventHandler <ObservablePropertyChangedEventArgs> [1];
_observedProperties = _observedProperties.Add(propertyInfo.Name, observedProperty);
}
int idx = 0;
while (idx < observedProperty.Handlers.Length && observedProperty.Handlers[idx] != null)
{
idx++;
}
if (idx == observedProperty.Handlers.Length)
{
var newHandlers = new EventHandler <ObservablePropertyChangedEventArgs> [idx * 2];
Array.Copy(observedProperty.Handlers, 0, newHandlers, 0, idx);
observedProperty.Handlers = newHandlers;
}
observedProperty.Handlers[idx] = handler;
}
protected override void OnObservedInstanceChanging(INotifyPropertyChanged oldInstance, INotifyPropertyChanged newInstance)
{
if (oldInstance != null)
{
oldInstance.PropertyChanged -= InvokeCallback;
}
if (newInstance != null)
{
newInstance.PropertyChanged += InvokeCallback;
}
if (_isInitialized)
{
PerformInvokeCallback();
}
if (newInstance == null)
{
_oldValue = default(T);
}
else
{
_oldValue = (T)ObservedProperty.GetValue(newInstance);
}
}
public void Callback_Is_Called_On_Direct_Property_Change()
{
bool isCallbackCalled = false;
var first = ObservedPropertyModels.CreateFirst("text");
Action callback = () => isCallbackCalled = true;
var property = ObservedProperty.Create(() => first.Second.Third.Value, callback);
first.Second.Third.Value = "new";
Assert.True(isCallbackCalled);
}
private void HandleNextPropertyChanged(object sender, PropertyChangedEventArgs args)
{
if (args.PropertyName != ObservedProperty.Name)
{
return;
}
var newValue = ObservedProperty.GetValue(ObservedInstance);
if (newValue != null && !(newValue is INotifyPropertyChanged))
{
throw new InvalidOperationException();
}
NextEntry.Reattach(newValue as INotifyPropertyChanged);
}
public void ObservedProperty_Dispose_Works()
{
bool isCallbackCalled = false;
var first = ObservedPropertyModels.CreateFirst("text");
Action callback = () => isCallbackCalled = true;
var property = ObservedProperty.Create(() => first.Second.Third.Value, callback);
property.Dispose();
first.Second = ObservedPropertyModels.CreateSecond("new1");
Assert.False(isCallbackCalled);
}
public ObservedPropertyNode(
MemberExpression expression,
ObservedProperty observer,
ObservedPropertyNode?previous)
{
ArgumentNullException.ThrowIfNull(expression);
ArgumentNullException.ThrowIfNull(observer);
this.objectAccessor = Expression.Lambda(expression.Expression !).Compile();
this.memberInfo = expression.Member;
this.observer = observer;
this.previous = previous;
this.UpdateObject();
}
protected virtual void Reattach(INotifyPropertyChanged observedInstance)
{
ObservedInstance = observedInstance;
if (observedInstance == null || NextEntry == null)
{
return;
}
var nextInstance = ObservedProperty.GetValue(ObservedInstance);
if (nextInstance != null && !(nextInstance is INotifyPropertyChanged))
{
throw new InvalidOperationException();
}
NextEntry.Reattach(nextInstance as INotifyPropertyChanged);
}
private void PerformInvokeCallback()
{
var newValue = ObservedInstance != null ? (T)ObservedProperty.GetValue(ObservedInstance) : default(T);
if (_oldValue == null && newValue == null)
{
return;
}
if (_oldValue != null && _oldValue.Equals(newValue))
{
return;
}
Callback?.Invoke(_oldValue, newValue);
_oldValue = newValue;
}
public void ObservedProperty_Suppress_Works()
{
bool isCallbackCalled = false;
var first = ObservedPropertyModels.CreateFirst("text");
Action callback = () => isCallbackCalled = true;
var property = ObservedProperty.Create(() => first.Second.Third.Value, callback);
using (property.Suppress())
first.Second = ObservedPropertyModels.CreateSecond("new");
Assert.False(isCallbackCalled);
first.Second = ObservedPropertyModels.CreateSecond("new1");
Assert.True(isCallbackCalled);
}
private string GetParamCode(ObservedProperty observedProperty)
{
return(observedProperty.CustomId.Split('-')[0].Trim());
}
