Imported Upstream version 4.0.0~alpha1

Former-commit-id: 806294f5ded97629b74c85c09952f2a74fe182d9

external/referencesource/System.Web/UI/ICallbackEventHandler.cs

@@ -0,0 +1,20 @@
+//------------------------------------------------------------------------------
+// <copyright file="ICallbackEventHandler.cs" company="Microsoft">
+//     Copyright (c) Microsoft Corporation.  All rights reserved.
+// </copyright>
+//------------------------------------------------------------------------------
+
+namespace System.Web.UI {
+    public interface ICallbackEventHandler {
+
+        /// <devdoc>
+        /// Process the eventargs that this control wanted fired from an out-of-band callback
+        /// </devdoc>
+        void RaiseCallbackEvent(string eventArgument);
+
+        /// <devdoc>
+        /// Render the control for the callback event
+        /// </devdoc>
+        string GetCallbackResult();
+    }
+}