Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

mcs/class/referencesource/System.Web.Extensions/ui/UpdatePanelTrigger.cs

@@ -0,0 +1,42 @@
+//------------------------------------------------------------------------------
+// <copyright file="UpdatePanelTrigger.cs" company="Microsoft">
+//     Copyright (c) Microsoft Corporation.  All rights reserved.
+// </copyright>
+//------------------------------------------------------------------------------
+ 
+namespace System.Web.UI {
+    using System;
+    using System.ComponentModel;
+    using System.Diagnostics;
+    using System.Web;
+
+    public abstract class UpdatePanelTrigger {
+#if DEBUG
+        private bool _initialized;
+#endif
+        private UpdatePanel _owner;
+
+        protected UpdatePanelTrigger() {
+        }
+
+        [Browsable(false)]
+        public UpdatePanel Owner {
+            get {
+                return _owner;
+            }
+        }
+
+        protected internal abstract bool HasTriggered();
+
+        protected internal virtual void Initialize() {
+#if DEBUG
+            Debug.Assert(!_initialized, "The trigger has already been initialized");
+            _initialized = true;
+#endif
+        }
+
+        internal void SetOwner(UpdatePanel owner) {
+            _owner = owner;
+        }
+    }
+}