Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

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

@@ -0,0 +1,74 @@
+//------------------------------------------------------------------------------
+// <copyright file="ControlUtil.cs" company="Microsoft">
+//     Copyright (c) Microsoft Corporation.  All rights reserved.
+// </copyright>
+//------------------------------------------------------------------------------
+ 
+using System;
+using System.Collections.Generic;
+using System.Text;
+using System.Web.Resources;
+using System.Web.UI;
+
+namespace System.Web.UI {
+    internal class ControlUtil {
+        internal static Control FindTargetControl(string controlID, Control control, bool searchNamingContainers) {
+            Control foundControl;
+            if (searchNamingContainers) {
+                Control currentContainer;
+                foundControl = null;
+
+                // DevDiv 73305: Do not assume starting control is not a naming container.
+                if (control is INamingContainer) {
+                    currentContainer = control;
+                }
+                else {
+                    currentContainer = control.NamingContainer;
+                }
+
+                do {
+                    foundControl = currentContainer.FindControl(controlID);
+                    currentContainer = currentContainer.NamingContainer;
+                }
+                while (foundControl == null && currentContainer != null);
+            }
+            else {
+                foundControl = control.FindControl(controlID);
+            }
+
+            return foundControl;
+        }
+
+        internal static bool IsBuiltInHiddenField(string hiddenFieldName) {
+            // Returns true is the field name represents a hidden field generated
+            // by ASP.NET's core runtime. This includes fields such as ViewState and
+            // EventValidation, but not ones generated by specific controls such as
+            // TreeView and WebParts.
+
+            // If the field is less than two chars long it's not built-in. (Perf)
+            if (hiddenFieldName.Length <= 2) {
+                return false;
+            }
+
+            // If it doesn't start with two underscores, it's not built-in. (Perf)
+            if (hiddenFieldName[0] != '_' ||
+                hiddenFieldName[1] != '_') {
+                return false;
+            }
+
+            // Examine list of built-in ASP.NET fields. The list was created by examining
+            // the ASP.NET source code for hidden field registration and rendering.
+            // We exclude __VIEWSTATEENCRYPTED and __VIEWSTATEFIELDCOUNT from the list
+            // since they're covered by the general __VIEWSTATE part.
+            return
+                hiddenFieldName.StartsWith("__VIEWSTATE", StringComparison.Ordinal) ||
+                String.Equals(hiddenFieldName, "__EVENTVALIDATION", StringComparison.Ordinal) ||
+                String.Equals(hiddenFieldName, "__LASTFOCUS", StringComparison.Ordinal) ||
+                String.Equals(hiddenFieldName, "__SCROLLPOSITIONX", StringComparison.Ordinal) ||
+                String.Equals(hiddenFieldName, "__SCROLLPOSITIONY", StringComparison.Ordinal) ||
+                String.Equals(hiddenFieldName, "__EVENTTARGET", StringComparison.Ordinal) ||
+                String.Equals(hiddenFieldName, "__EVENTARGUMENT", StringComparison.Ordinal) ||
+                String.Equals(hiddenFieldName, "__PREVIOUSPAGE", StringComparison.Ordinal);
+        }
+    }
+}