public void Subscribe(INotifyPropertyChanged handler)
{
// If we're reapplying, we don't want to double subscribe
Unsubscribe();
_listener = new WeakPropertyChangedProxy(handler, _changeHandler);
}
public void Unsubscribe()
{
var listener = _listener;
if (listener != null)
{
listener.Unsubscribe();
_listener = null;
}
}
public void Subscribe(INotifyPropertyChanged handler)
{
if (ReferenceEquals(handler, _listener?.Source?.Target))
{
// Already subscribed
return;
}
// Clear out the old subscription if necessary
Unsubscribe();
_listener = new WeakPropertyChangedProxy(handler, _changeHandler);
}
public void Subscribe(INotifyPropertyChanged handler)
{
INotifyPropertyChanged source;
if (_listener != null && _listener.Source.TryGetTarget(out source) && ReferenceEquals(handler, source))
{
// Already subscribed
return;
}
// Clear out the old subscription if necessary
Unsubscribe();
_listener = new WeakPropertyChangedProxy(handler, _changeHandler);
}
public MethodToCommandConverter(Delegate action)
{
var target = action.Target;
var canExecuteMethodName = "Can" + action.Method.Name;
var parameters = action.Method.GetParameters();
var parameterInfo = parameters.Length == 0 ? null : parameters[0].ParameterType;
if (parameterInfo == null)
{
execute = CreateExecute(target, action.Method);
}
else
{
execute = CreateExecute(target, action.Method, parameterInfo);
}
var canExecuteMethod = action.Method.DeclaringType.GetRuntimeMethods()
.FirstOrDefault(m => m.Name == canExecuteMethodName &&
m.GetParameters().Length == 1 &&
m.GetParameters()[0].ParameterType == typeof(object));
if (canExecuteMethod == null)
{
canExecute = AlwaysEnabled;
}
else
{
canExecute = CreateCanExecute(target, canExecuteMethod);
dependencyProperties = canExecuteMethod
.GetCustomAttributes(typeof(Metadata.DependsOnAttribute), true)
.OfType <Metadata.DependsOnAttribute>()
.Select(x => x.Name)
.ToArray();
if (dependencyProperties.Any() &&
target is INotifyPropertyChanged inpc)
{
propertyChangedEventHandler = OnPropertyChanged;
weakPropertyChanged = new WeakPropertyChangedProxy(inpc, propertyChangedEventHandler);
}
}
}
