Imported Upstream version 4.0.0~alpha1

Former-commit-id: 806294f5ded97629b74c85c09952f2a74fe182d9

external/referencesource/System/sys/system/configuration/IApplicationSettingsProvider.cs

@@ -0,0 +1,36 @@
+//------------------------------------------------------------------------------
+// <copyright file="IApplicationSettingsProvider.cs" company="Microsoft">
+//     Copyright (c) Microsoft Corporation.  All rights reserved.
+// </copyright>                                                                
+//------------------------------------------------------------------------------
+
+namespace System.Configuration {
+
+    using System.Security.Permissions;
+
+    /// <devdoc>
+    ///     This interface is an extension to SettingsProvider that a provider can implement
+    ///     to support additional functionality for settings classes that derive from ApplicationSettingsBase.
+    /// </devdoc>
+    public interface IApplicationSettingsProvider {
+        /// <devdoc>
+        ///    Retrieves the previous value of a given SettingsProperty. This is used in conjunction with Upgrade.
+        /// </devdoc>
+        [PermissionSet(SecurityAction.LinkDemand, Name="FullTrust")]
+        SettingsPropertyValue GetPreviousVersion(SettingsContext context, SettingsProperty property);
+
+        /// <devdoc>
+        ///     Resets all settings to their "default" values.      
+        /// </devdoc>
+        [PermissionSet(SecurityAction.LinkDemand, Name="FullTrust")]
+        void Reset(SettingsContext context);
+
+        /// <devdoc>
+        ///    Indicates to the provider that the app has been upgraded. This is a chance for the provider to upgrade
+        ///    its stored settings as appropriate.
+        /// </devdoc>
+        [PermissionSet(SecurityAction.LinkDemand, Name="FullTrust")]
+        void Upgrade(SettingsContext context, SettingsPropertyCollection properties);
+    }
+}
+