chore: separated System.Windows.Interactivity code

src/Shared/System.Windows.Interactivity/TriggerActionCollection.cs

@@ -0,0 +1,45 @@
+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();
+    }
+}