support for .NET framework 3.5

Still have bugs

Net35/HandyControl_Net35/Interactivity/TriggerActionCollection.cs

@@ -0,0 +1,46 @@
+using System;
+using System.Windows;
+
+namespace HandyControl.Interactivity
+{
+    public class TriggerActionCollection : AttachableCollection<TriggerAction>
+    {
+        internal TriggerActionCollection()
+        {
+        }
+
+        protected override Freezable CreateInstanceCore()
+        {
+            return new TriggerActionCollection();
+        }
+
+        internal override void ItemAdded(TriggerAction item)
+        {
+            if (item.IsHosted)
+                throw new InvalidOperationException(ExceptionStringTable
+                    .CannotHostTriggerActionMultipleTimesExceptionMessage);
+            if (AssociatedObject != null)
+                item.Attach(AssociatedObject);
+            item.IsHosted = true;
+        }
+
+        internal override void ItemRemoved(TriggerAction item)
+        {
+            if (((IAttachedObject) item).AssociatedObject != null)
+                item.Detach();
+            item.IsHosted = false;
+        }
+
+        protected override void OnAttached()
+        {
+            foreach (var action in this)
+                action.Attach(AssociatedObject);
+        }
+
+        protected override void OnDetaching()
+        {
+            foreach (var action in this)
+                action.Detach();
+        }
+    }
+}