Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

mcs/class/referencesource/System.Web/UI/InternalControlCollection.cs

@@ -0,0 +1,32 @@
+//------------------------------------------------------------------------------
+// <copyright file="InternalControlCollection.cs" company="Microsoft">
+//     Copyright (c) Microsoft Corporation.  All rights reserved.
+// </copyright>                                                                
+//------------------------------------------------------------------------------
+
+namespace System.Web.UI {
+
+    /// <devdoc>
+    ///    <para>
+    ///       Represents a ControlCollection that controls can only be added to internally.
+    ///    </para>
+    /// </devdoc>
+    internal class InternalControlCollection : ControlCollection {
+
+        internal InternalControlCollection(Control owner) : base(owner) {
+        }
+
+        private void ThrowNotSupportedException() {
+            throw new HttpException(SR.GetString(SR.Control_does_not_allow_children,
+                                                                     Owner.GetType().ToString()));
+        }
+
+        public override void Add(Control child) {
+            ThrowNotSupportedException();
+        }
+
+        public override void AddAt(int index, Control child) {
+            ThrowNotSupportedException();
+        }
+    }
+}