Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

mcs/class/referencesource/System.Configuration/System/Configuration/CallbackValidatorAttribute.cs

@@ -0,0 +1,80 @@
+//------------------------------------------------------------------------------
+// <copyright file="CallbackValidatorAttribute.cs" company="Microsoft">
+//     Copyright (c) Microsoft Corporation.  All rights reserved.
+// </copyright>
+//------------------------------------------------------------------------------
+
+using System;
+using System.Configuration.Internal;
+using System.Collections;
+using System.Collections.Specialized;
+using System.Collections.Generic;
+using System.IO;
+using System.Reflection;
+using System.Security.Permissions;
+using System.Xml;
+using System.Globalization;
+using System.ComponentModel;
+using System.Security;
+using System.Text;
+
+namespace System.Configuration {
+
+    [AttributeUsage(AttributeTargets.Property)]
+    public sealed class CallbackValidatorAttribute : ConfigurationValidatorAttribute {
+        private Type _type = null;
+        private String _callbackMethodName = String.Empty;
+        private ValidatorCallback _callbackMethod;
+
+        public override ConfigurationValidatorBase ValidatorInstance {
+            get {
+                if (_callbackMethod == null) {
+                    if (_type == null) {
+                        throw new ArgumentNullException("Type");
+                    }
+                    if (!String.IsNullOrEmpty(_callbackMethodName)) {
+                        MethodInfo methodInfo = _type.GetMethod(_callbackMethodName, BindingFlags.Public | BindingFlags.Static);
+                        if (methodInfo != null) {
+                            ParameterInfo[] parameters = methodInfo.GetParameters();
+                            if ((parameters.Length == 1) && (parameters[0].ParameterType == typeof(Object))) {
+                                // The security here depends on nobody changing the type or callback method once the declaring type has been
+                                // set. This currently isn't an issue since the attribute is instantiated then the declaring type is set without
+                                // user code having gotten a chance to run in between. But if the behavior of PropertyInfo.GetAttributes ever
+                                // changes such that it returns cached attribute instances rather than new instances every time, this assumption is void.
+                                _callbackMethod = (ValidatorCallback)TypeUtil.CreateDelegateRestricted(_declaringType, typeof(ValidatorCallback), methodInfo);
+                            }
+                        }
+                    }
+                }
+                if (_callbackMethod == null) {
+                    throw new System.ArgumentException(SR.GetString(SR.Validator_method_not_found, _callbackMethodName));
+                }
+
+                return new CallbackValidator(_callbackMethod);
+            }
+        }
+
+        public CallbackValidatorAttribute() {
+        }
+
+        public Type Type {
+            get {
+                return _type;
+            }
+            set {
+                _type = value;
+                _callbackMethod = null;
+            }
+        }
+
+        public String CallbackMethodName {
+            get {
+                return _callbackMethodName;
+            }
+            set {
+                _callbackMethodName = value;
+                _callbackMethod = null;
+            }
+        }
+    }
+}