void ReturnListener()
{
listener.Changed -= HandleValueChanged;
freeListeners.Add(listener);
listener = null;
}
void Attach()
{
Detach();
if (target != null && binding != null)
{
listener = GetListener();
listener.Attach(target, binding);
}
}
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);
}
void Attach()
{
Detach();
if (target != null && binding != null)
{
listener = GetListener();
listener.Attach(target, binding);
}
}
void ReturnListener()
{
listener.Changed -= HandleValueChanged;
freeListeners.Add(listener);
listener = null;
}
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;
}
static void element_Loaded(object sender, RoutedEventArgs e)
{
FrameworkElement element = (FrameworkElement)sender;
element.Loaded -= element_Loaded;
ScrollViewer scrollViewer = FindChildOfType <ScrollViewer>(element);
if (scrollViewer == null)
{
throw new InvalidOperationException("ScrollViewer not found.");
}
var listener = new DependencyPropertyListener();
listener.Changed
+= delegate
{
// This bool denotes first load when an xaml element is loaded with no elements
bool firstLoad = (Math.Round(scrollViewer.VerticalOffset) == 0) &&
(Math.Round(scrollViewer.ScrollableHeight) == 0);
bool atBottom = Math.Round(scrollViewer.VerticalOffset)
>= Math.Round(scrollViewer.ScrollableHeight);
if (atBottom && !firstLoad)
{
//GlobalLoading.Instance.IsLoading = true;
if (element.Name.Equals("recentPictures"))
{
foreach (PictureInfo p in App.ContinuedRecentPictures)
{
App.RecentPictures.Add(p);
}
App.ContinuedRecentPictures.Clear();
}
else if (element.Name.Equals("UserPictures"))
{
int count = 0;
int numberOfPicturesPerLoad = 24;
foreach (PictureInfo p in UserDetailPage.ContinuedUserPictures)
{
// Only load 24 PictureInfo objects at a time
if (count < numberOfPicturesPerLoad)
{
App.UserPictures.Add(p);
count++;
}
else
{
break;
}
}
// Now we delete those PictureInfo objects that were added
for (int i = 0; i < numberOfPicturesPerLoad; i++)
{
if (UserDetailPage.ContinuedUserPictures.Count == 0)
{
break;
}
UserDetailPage.ContinuedUserPictures.RemoveAt(0);
}
}
/*
* var atEnd = GetAtEndCommand(element);
* if (atEnd != null)
* {
* atEnd.Execute(null);
* }*/
}
};
Binding binding = new Binding("VerticalOffset")
{
Source = scrollViewer
};
listener.Attach(scrollViewer, binding);
}
