private void AssociatedObject_LayoutUpdated()

in src/Microsoft.Xaml.Behaviors/Layout/FluidMoveBehavior.cs [131:187]

• 46 lines of code
• 11 McCabe index (conditional complexity)

        private void AssociatedObject_LayoutUpdated(object sender, EventArgs e)
        {
            if (!this.IsActive)
            {
                return;
            }

            // if it's been long enough since our last purge, then let's kick one off. Since we can't control how often layout runs, and some
            // objects could reappear on the very next layout pass, we'll purge any tag who hasn't been seen since the purge tick before that.
            //
            // If we got a notification when elements were deleted, we would maintain a far shorter list of tags whose FEs were deleted since the last purge.
            // 
            // We might also be able to use a WeakReference solution here, but this one is pretty cheap as it only runs when Layout is running anyway.
            if (DateTime.Now - lastPurgeTick >= minTickDelta)
            {
                List<object> deadTags = null;

                foreach (KeyValuePair<object, TagData> pair in TagDictionary)
                {
                    if (pair.Value.Timestamp < nextToLastPurgeTick)
                    {
                        if (deadTags == null)
                        {
                            deadTags = new List<object>();
                        }
                        deadTags.Add(pair.Key);
                    }
                }

                if (deadTags != null)
                {
                    foreach (object tag in deadTags)
                    {
                        TagDictionary.Remove(tag);
                    }
                }

                nextToLastPurgeTick = lastPurgeTick;
                lastPurgeTick = DateTime.Now;
            }

            if (this.AppliesTo == FluidMoveScope.Self)
            {
                this.UpdateLayoutTransition(this.AssociatedObject);
            }
            else
            {
                Panel panel = this.AssociatedObject as Panel;
                if (panel != null)
                {
                    foreach (FrameworkElement child in panel.Children)
                    {
                        this.UpdateLayoutTransition(child);
                    }
                }
            }
        }