/// <summary>
/// Attaches the source.
/// </summary>
/// <param name="source">
/// The source.
/// </param>
protected override void AttachSource(object source)
{
base.AttachSource(source);
if (source != null && source.GetType().ContainsEvent(WeakCollectionBinding.CollectionChangedEventName))
{
if (collectionWeakEvent != null)
{
collectionWeakEvent.DetachEvent();
}
if (collectionWeakEvent == null)
{
collectionWeakEvent = new WeakEvent(this);
}
collectionWeakEvent.AttachEvent(source, null, WeakCollectionBinding.CollectionChangedEventName, "OnSourceCollectionChanged");
}
}
public void Test_MemoryLeak_WeakEvent()
{
// 1. Normal Event will hold the strong reference which prevent the GC collect.
var view = new TestView();
var viewModel = new TestViewModel();
var reference = new WeakReference(view);
viewModel.TestViewModelEvent += view.OnEventOccured;
viewModel.RaiseTestViewModelEvent();
Assert.AreEqual(1, view.EventCount);
Assert.AreEqual(1, viewModel.GetTestViewModelEventInvocationCount());
view = null;
GC.Collect();
Assert.IsTrue(reference.IsAlive); // Still live
viewModel.TestViewModelEvent -= reference.GetTarget<TestView>().OnEventOccured;
GC.Collect();
GC.WaitForPendingFinalizers();
GC.Collect();
Assert.IsFalse(reference.IsAlive);
reference = null;
Assert.IsNull(reference.GetTarget<TestView>());
// 2. WeakEvent hold the weak reference which will not prevent GC collect.
var view2 = new TestView();
var viewModel2 = new TestViewModel();
var reference2 = new WeakReference(view2);
var weakEvent = new WeakEvent(view2);
weakEvent.AttachEvent(viewModel2, null, "TestViewModelEvent", "OnEventOccured");
viewModel2.RaiseTestViewModelEvent();
Assert.AreEqual(1, view2.EventCount);
view2 = null;
GC.Collect();
Assert.IsFalse(reference2.IsAlive);
viewModel2.RaiseTestViewModelEvent();
Assert.AreEqual(0, viewModel2.GetTestViewModelEventInvocationCount());
}
