Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

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

@@ -0,0 +1,86 @@
+//------------------------------------------------------------------------------
+// <copyright file="KeyValueConfigurationElement.cs" company="Microsoft">
+//     Copyright (c) Microsoft Corporation.  All rights reserved.
+// </copyright>
+//------------------------------------------------------------------------------
+
+namespace System.Configuration {
+    using System;
+    using System.Xml;
+    using System.Configuration;
+    using System.Collections.Specialized;
+    using System.Collections;
+    using System.IO;
+    using System.Text;
+
+    public class KeyValueConfigurationElement : ConfigurationElement {
+        private static ConfigurationPropertyCollection _properties;
+        private static readonly ConfigurationProperty _propKey =
+            new ConfigurationProperty("key", typeof(string), String.Empty, ConfigurationPropertyOptions.IsKey | ConfigurationPropertyOptions.IsRequired);
+        private static readonly ConfigurationProperty _propValue =
+            new ConfigurationProperty("value", typeof(string), String.Empty, ConfigurationPropertyOptions.None);
+
+        static KeyValueConfigurationElement() {
+            // Property initialization
+            _properties = new ConfigurationPropertyCollection();
+            _properties.Add(_propKey);
+            _properties.Add(_propValue);
+        }
+
+        protected internal override ConfigurationPropertyCollection Properties {
+            get {
+                return _properties;
+            }
+        }
+
+        bool _needsInit;
+        string _initKey;
+        string _initValue;
+
+        //
+        // Constructor
+        //
+        internal KeyValueConfigurationElement() {
+        }
+
+        public KeyValueConfigurationElement(string key, string value) {
+            _needsInit = true;
+            _initKey = key;
+            _initValue = value;
+        }
+
+        protected internal override void Init() {
+            base.Init();
+
+            // We cannot initialize configuration properties in the constructor,
+            // because Properties is an overridable virtual property that 
+            // hence may not be available in the constructor.
+            if (_needsInit) {
+                _needsInit = false;
+                base[_propKey] = _initKey;
+                Value = _initValue;
+            }
+        }
+
+        //
+        // Properties
+        //
+
+        [ConfigurationProperty("key", Options = ConfigurationPropertyOptions.IsKey, DefaultValue = "")]
+        public string Key {
+            get {
+                return (string)base[_propKey];
+            }
+        }
+
+        [ConfigurationProperty("value", DefaultValue = "")]
+        public string Value {
+            get {
+                return (string)base[_propValue];
+            }
+            set {
+                base[_propValue] = value;
+            }
+        }
+    }
+}