Adjust project structure

src/Shared/HandyControl_Shared/Interactivity/EventTriggerBase!1.cs

@@ -0,0 +1,21 @@
+namespace HandyControl.Interactivity
+{
+    public abstract class EventTriggerBase<T> : EventTriggerBase where T : class
+    {
+        protected EventTriggerBase() : base(typeof(T))
+        {
+        }
+
+        protected virtual void OnSourceChanged(T oldSource, T newSource)
+        {
+        }
+
+        internal sealed override void OnSourceChangedImpl(object oldSource, object newSource)
+        {
+            base.OnSourceChangedImpl(oldSource, newSource);
+            OnSourceChanged(oldSource as T, newSource as T);
+        }
+
+        public new T Source => (T)base.Source;
+    }
+}