From dfcde1b190051c3d62a601a834ccee54c12d6089 Mon Sep 17 00:00:00 2001
From: Hao Kung <HaoK@users.noreply.github.com>
Date: Tue, 28 Aug 2018 15:46:17 -0700
Subject: [PATCH] Add DataAnnotations based validation (#272)

---
 Options.sln                                   |   7 ++
 build/dependencies.props                      |   1 +
 .../ConfigurationChangeTokenSource.cs         |   3 +
 ...ons.Options.ConfigurationExtensions.csproj |   2 +-
 .../DataAnnotationValidateOptions.cs          |  61 ++++++++++
 ....Extensions.Options.DataAnnotations.csproj |  20 ++++
 ...OptionsBuilderDataAnnotationsExtensions.cs |  25 ++++
 .../baseline.netcore.json                     |   2 +
 .../ConfigureNamedOptions.cs                  | 102 +++++++++++++++-
 src/Microsoft.Extensions.Options/IOptions.cs  |   2 +-
 .../Microsoft.Extensions.Options.csproj       |   3 +-
 src/Microsoft.Extensions.Options/Options.cs   |   3 +
 .../OptionsBuilder.cs                         | 103 ++++++++++++++++-
 .../OptionsFactory.cs                         |   3 +
 .../OptionsManager.cs                         |   8 +-
 .../OptionsMonitor.cs                         |   3 +
 .../OptionsValidationException.cs             |   6 +
 .../PostConfigureOptions.cs                   |  93 ++++++++++++++-
 .../ValidateOptions.cs                        |  12 ++
 .../Microsoft.Extensions.Options.Test.csproj  |   1 +
 .../OptionsBuilderTest.cs                     | 109 +++++++++++++++++-
 21 files changed, 551 insertions(+), 18 deletions(-)
 create mode 100644 src/Microsoft.Extensions.Options.DataAnnotations/DataAnnotationValidateOptions.cs
 create mode 100644 src/Microsoft.Extensions.Options.DataAnnotations/Microsoft.Extensions.Options.DataAnnotations.csproj
 create mode 100644 src/Microsoft.Extensions.Options.DataAnnotations/OptionsBuilderDataAnnotationsExtensions.cs
 create mode 100644 src/Microsoft.Extensions.Options.DataAnnotations/baseline.netcore.json

diff --git a/Options.sln b/Options.sln
index ce4ce7216f5..92d6737e7c7 100644
--- a/Options.sln
+++ b/Options.sln
@@ -37,6 +37,8 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Solution Items", "Solution
 		version.xml = version.xml
 	EndProjectSection
 EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Microsoft.Extensions.Options.DataAnnotations", "src\Microsoft.Extensions.Options.DataAnnotations\Microsoft.Extensions.Options.DataAnnotations.csproj", "{D0EB1487-D9E9-4C58-A907-BCD595993251}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -55,6 +57,10 @@ Global
 		{BA4EF3CE-1829-4E0E-8281-BD503FF8A682}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{BA4EF3CE-1829-4E0E-8281-BD503FF8A682}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{BA4EF3CE-1829-4E0E-8281-BD503FF8A682}.Release|Any CPU.Build.0 = Release|Any CPU
+		{D0EB1487-D9E9-4C58-A907-BCD595993251}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{D0EB1487-D9E9-4C58-A907-BCD595993251}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{D0EB1487-D9E9-4C58-A907-BCD595993251}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{D0EB1487-D9E9-4C58-A907-BCD595993251}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -63,6 +69,7 @@ Global
 		{16BADE2F-1184-4518-8A70-B68A19D0805B} = {0A4664A0-CB48-4338-A6B7-02E28DF62CBA}
 		{6ACF4BAB-2F09-4DA6-B273-27E4282865EB} = {10221BD9-FD19-4809-B680-7628CB87926B}
 		{BA4EF3CE-1829-4E0E-8281-BD503FF8A682} = {10221BD9-FD19-4809-B680-7628CB87926B}
+		{D0EB1487-D9E9-4C58-A907-BCD595993251} = {10221BD9-FD19-4809-B680-7628CB87926B}
 	EndGlobalSection
 	GlobalSection(ExtensibilityGlobals) = postSolution
 		SolutionGuid = {A4D0BBDB-82DD-4B7E-981F-E6B90F3850B6}
diff --git a/build/dependencies.props b/build/dependencies.props
index 299dca8da49..19f487de01c 100644
--- a/build/dependencies.props
+++ b/build/dependencies.props
@@ -13,6 +13,7 @@
     <MicrosoftNETCoreApp21PackageVersion>2.1.2</MicrosoftNETCoreApp21PackageVersion>
     <MicrosoftNETCoreApp22PackageVersion>2.2.0-preview1-26618-02</MicrosoftNETCoreApp22PackageVersion>
     <MicrosoftNETTestSdkPackageVersion>15.6.1</MicrosoftNETTestSdkPackageVersion>
+    <SystemComponentModelAnnotationsPackageVersion>4.6.0-preview1-26617-01</SystemComponentModelAnnotationsPackageVersion>
     <NETStandardLibrary20PackageVersion>2.0.3</NETStandardLibrary20PackageVersion>
     <XunitPackageVersion>2.3.1</XunitPackageVersion>
     <XunitRunnerVisualStudioPackageVersion>2.4.0</XunitRunnerVisualStudioPackageVersion>
diff --git a/src/Microsoft.Extensions.Options.ConfigurationExtensions/ConfigurationChangeTokenSource.cs b/src/Microsoft.Extensions.Options.ConfigurationExtensions/ConfigurationChangeTokenSource.cs
index 29a2d382307..b02aed0832e 100644
--- a/src/Microsoft.Extensions.Options.ConfigurationExtensions/ConfigurationChangeTokenSource.cs
+++ b/src/Microsoft.Extensions.Options.ConfigurationExtensions/ConfigurationChangeTokenSource.cs
@@ -37,6 +37,9 @@ public ConfigurationChangeTokenSource(string name, IConfiguration config)
             Name = name ?? Options.DefaultName;
         }
 
+        /// <summary>
+        /// The name of the option instance being changed.
+        /// </summary>
         public string Name { get; }
 
         /// <summary>
diff --git a/src/Microsoft.Extensions.Options.ConfigurationExtensions/Microsoft.Extensions.Options.ConfigurationExtensions.csproj b/src/Microsoft.Extensions.Options.ConfigurationExtensions/Microsoft.Extensions.Options.ConfigurationExtensions.csproj
index 283f524d902..8d68cb58a13 100644
--- a/src/Microsoft.Extensions.Options.ConfigurationExtensions/Microsoft.Extensions.Options.ConfigurationExtensions.csproj
+++ b/src/Microsoft.Extensions.Options.ConfigurationExtensions/Microsoft.Extensions.Options.ConfigurationExtensions.csproj
@@ -3,7 +3,7 @@
   <PropertyGroup>
     <Description>Provides additional configuration specific functionality related to Options.</Description>
     <TargetFramework>netstandard2.0</TargetFramework>
-    <NoWarn>$(NoWarn);CS1591</NoWarn>
+    <NoWarn>$(NoWarn)</NoWarn>
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
     <PackageTags>aspnetcore;configuration;options</PackageTags>
   </PropertyGroup>
diff --git a/src/Microsoft.Extensions.Options.DataAnnotations/DataAnnotationValidateOptions.cs b/src/Microsoft.Extensions.Options.DataAnnotations/DataAnnotationValidateOptions.cs
new file mode 100644
index 00000000000..4dd784d6723
--- /dev/null
+++ b/src/Microsoft.Extensions.Options.DataAnnotations/DataAnnotationValidateOptions.cs
@@ -0,0 +1,61 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.DataAnnotations;
+using System.Linq;
+
+namespace Microsoft.Extensions.Options
+{
+    /// <summary>
+    /// Implementation of <see cref="IValidateOptions{TOptions}"/> that uses DataAnnotation's <see cref="Validator"/> for validation.
+    /// </summary>
+    /// <typeparam name="TOptions">The instance being validated.</typeparam>
+    public class DataAnnotationValidateOptions<TOptions> : IValidateOptions<TOptions> where TOptions : class
+    {
+        /// <summary>
+        /// Constructor.
+        /// </summary>
+        /// <param name="name"></param>
+        public DataAnnotationValidateOptions(string name)
+        {
+            Name = name;
+        }
+
+        /// <summary>
+        /// The options name.
+        /// </summary>
+        public string Name { get; }
+
+        /// <summary>
+        /// Validates a specific named options instance (or all when name is null).
+        /// </summary>
+        /// <param name="name">The name of the options instance being validated.</param>
+        /// <param name="options">The options instance.</param>
+        /// <returns>The <see cref="ValidateOptionsResult"/> result.</returns>
+        public ValidateOptionsResult Validate(string name, TOptions options)
+        {
+            // Null name is used to configure all named options.
+            if (Name == null || name == Name)
+            {
+                var validationResults = new List<ValidationResult>();
+                if (Validator.TryValidateObject(options,
+                    new ValidationContext(options, serviceProvider: null, items: null), 
+                    validationResults, 
+                    validateAllProperties: true))
+                {
+                    return ValidateOptionsResult.Success;
+                }
+
+                return ValidateOptionsResult.Fail(String.Join(Environment.NewLine,
+                    validationResults.Select(r => "DataAnnotation validation failed for members " +
+                        String.Join(", ", r.MemberNames) +
+                        " with the error '" + r.ErrorMessage + "'.")));
+            }
+
+            // Ignored if not validating this instance.
+            return ValidateOptionsResult.Skip;
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/Microsoft.Extensions.Options.DataAnnotations/Microsoft.Extensions.Options.DataAnnotations.csproj b/src/Microsoft.Extensions.Options.DataAnnotations/Microsoft.Extensions.Options.DataAnnotations.csproj
new file mode 100644
index 00000000000..c15084b4959
--- /dev/null
+++ b/src/Microsoft.Extensions.Options.DataAnnotations/Microsoft.Extensions.Options.DataAnnotations.csproj
@@ -0,0 +1,20 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <Description>Provides additional DataAnnotations specific functionality related to Options.</Description>
+    <TargetFramework>netstandard2.0</TargetFramework>
+    <NoWarn>$(NoWarn)</NoWarn>
+    <GenerateDocumentationFile>true</GenerateDocumentationFile>
+    <PackageTags>aspnetcore;validation;options</PackageTags>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\Microsoft.Extensions.Options\Microsoft.Extensions.Options.csproj" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.Extensions.DependencyInjection.Abstractions" Version="$(MicrosoftExtensionsDependencyInjectionAbstractionsPackageVersion)" />
+    <PackageReference Include="System.ComponentModel.Annotations" Version="$(SystemComponentModelAnnotationsPackageVersion)" />
+  </ItemGroup>
+
+</Project>
diff --git a/src/Microsoft.Extensions.Options.DataAnnotations/OptionsBuilderDataAnnotationsExtensions.cs b/src/Microsoft.Extensions.Options.DataAnnotations/OptionsBuilderDataAnnotationsExtensions.cs
new file mode 100644
index 00000000000..1df05d4a330
--- /dev/null
+++ b/src/Microsoft.Extensions.Options.DataAnnotations/OptionsBuilderDataAnnotationsExtensions.cs
@@ -0,0 +1,25 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using Microsoft.Extensions.Options;
+
+namespace Microsoft.Extensions.DependencyInjection
+{
+    /// <summary>
+    /// Extension methods for adding configuration related options services to the DI container via <see cref="OptionsBuilder{TOptions}"/>.
+    /// </summary>
+    public static class OptionsBuilderDataAnnotationsExtensions
+    {
+        /// <summary>
+        /// Register this options instance for validation of its DataAnnotations.
+        /// </summary>
+        /// <typeparam name="TOptions">The options type to be configured.</typeparam>
+        /// <param name="optionsBuilder">The options builder to add the services to.</param>
+        /// <returns>The <see cref="OptionsBuilder{TOptions}"/> so that additional calls can be chained.</returns>
+        public static OptionsBuilder<TOptions> ValidateDataAnnotations<TOptions>(this OptionsBuilder<TOptions> optionsBuilder) where TOptions : class
+        {
+            optionsBuilder.Services.AddSingleton<IValidateOptions<TOptions>>(new DataAnnotationValidateOptions<TOptions>(optionsBuilder.Name));
+            return optionsBuilder;
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/Microsoft.Extensions.Options.DataAnnotations/baseline.netcore.json b/src/Microsoft.Extensions.Options.DataAnnotations/baseline.netcore.json
new file mode 100644
index 00000000000..7a73a41bfdf
--- /dev/null
+++ b/src/Microsoft.Extensions.Options.DataAnnotations/baseline.netcore.json
@@ -0,0 +1,2 @@
+{
+}
\ No newline at end of file
diff --git a/src/Microsoft.Extensions.Options/ConfigureNamedOptions.cs b/src/Microsoft.Extensions.Options/ConfigureNamedOptions.cs
index e860d38d596..702be8181ff 100644
--- a/src/Microsoft.Extensions.Options/ConfigureNamedOptions.cs
+++ b/src/Microsoft.Extensions.Options/ConfigureNamedOptions.cs
@@ -35,8 +35,8 @@ public ConfigureNamedOptions(string name, Action<TOptions> action)
         /// <summary>
         /// Invokes the registered configure Action if the name matches.
         /// </summary>
-        /// <param name="name"></param>
-        /// <param name="options"></param>
+        /// <param name="name">The name of the options instance being configured.</param>
+        /// <param name="options">The options instance to configure.</param>
         public virtual void Configure(string name, TOptions options)
         {
             if (options == null)
@@ -51,6 +51,10 @@ public virtual void Configure(string name, TOptions options)
             }
         }
 
+        /// <summary>
+        /// Invoked to configure a TOptions instance with the <see cref="Options.DefaultName"/>.
+        /// </summary>
+        /// <param name="options">The options instance to configure.</param>
         public void Configure(TOptions options) => Configure(Options.DefaultName, options);
     }
 
@@ -86,8 +90,16 @@ public ConfigureNamedOptions(string name, TDep dependency, Action<TOptions, TDep
         /// </summary>
         public Action<TOptions, TDep> Action { get; }
 
+        /// <summary>
+        /// The dependency.
+        /// </summary>
         public TDep Dependency { get; }
 
+        /// <summary>
+        /// Invokes the registered configure Action if the name matches.
+        /// </summary>
+        /// <param name="name">The name of the options instance being configured.</param>
+        /// <param name="options">The options instance to configure.</param>
         public virtual void Configure(string name, TOptions options)
         {
             if (options == null)
@@ -102,6 +114,10 @@ public virtual void Configure(string name, TOptions options)
             }
         }
 
+        /// <summary>
+        /// Invoked to configure a TOptions instance with the <see cref="Options.DefaultName"/>.
+        /// </summary>
+        /// <param name="options">The options instance to configure.</param>
         public void Configure(TOptions options) => Configure(Options.DefaultName, options);
     }
 
@@ -141,10 +157,21 @@ public ConfigureNamedOptions(string name, TDep1 dependency, TDep2 dependency2, A
         /// </summary>
         public Action<TOptions, TDep1, TDep2> Action { get; }
 
+        /// <summary>
+        /// The first dependency.
+        /// </summary>
         public TDep1 Dependency1 { get; }
 
+        /// <summary>
+        /// The second dependency.
+        /// </summary>
         public TDep2 Dependency2 { get; }
 
+        /// <summary>
+        /// Invokes the registered configure Action if the name matches.
+        /// </summary>
+        /// <param name="name">The name of the options instance being configured.</param>
+        /// <param name="options">The options instance to configure.</param>
         public virtual void Configure(string name, TOptions options)
         {
             if (options == null)
@@ -159,6 +186,10 @@ public virtual void Configure(string name, TOptions options)
             }
         }
 
+        /// <summary>
+        /// Invoked to configure a TOptions instance with the <see cref="Options.DefaultName"/>.
+        /// </summary>
+        /// <param name="options">The options instance to configure.</param>
         public void Configure(TOptions options) => Configure(Options.DefaultName, options);
     }
 
@@ -202,13 +233,26 @@ public ConfigureNamedOptions(string name, TDep1 dependency, TDep2 dependency2, T
         /// </summary>
         public Action<TOptions, TDep1, TDep2, TDep3> Action { get; }
 
+        /// <summary>
+        /// The first dependency.
+        /// </summary>
         public TDep1 Dependency1 { get; }
 
+        /// <summary>
+        /// The second dependency.
+        /// </summary>
         public TDep2 Dependency2 { get; }
 
+        /// <summary>
+        /// The third dependency.
+        /// </summary>
         public TDep3 Dependency3 { get; }
 
-
+        /// <summary>
+        /// Invokes the registered configure Action if the name matches.
+        /// </summary>
+        /// <param name="name">The name of the options instance being configured.</param>
+        /// <param name="options">The options instance to configure.</param>
         public virtual void Configure(string name, TOptions options)
         {
             if (options == null)
@@ -223,6 +267,10 @@ public virtual void Configure(string name, TOptions options)
             }
         }
 
+        /// <summary>
+        /// Invoked to configure a TOptions instance with the <see cref="Options.DefaultName"/>.
+        /// </summary>
+        /// <param name="options">The options instance to configure.</param>
         public void Configure(TOptions options) => Configure(Options.DefaultName, options);
     }
 
@@ -270,15 +318,31 @@ public ConfigureNamedOptions(string name, TDep1 dependency1, TDep2 dependency2,
         /// </summary>
         public Action<TOptions, TDep1, TDep2, TDep3, TDep4> Action { get; }
 
+        /// <summary>
+        /// The first dependency.
+        /// </summary>
         public TDep1 Dependency1 { get; }
 
+        /// <summary>
+        /// The second dependency.
+        /// </summary>
         public TDep2 Dependency2 { get; }
 
+        /// <summary>
+        /// The third dependency.
+        /// </summary>
         public TDep3 Dependency3 { get; }
 
+        /// <summary>
+        /// The fourth dependency.
+        /// </summary>
         public TDep4 Dependency4 { get; }
 
-
+        /// <summary>
+        /// Invokes the registered configure Action if the name matches.
+        /// </summary>
+        /// <param name="name">The name of the options instance being configured.</param>
+        /// <param name="options">The options instance to configure.</param>
         public virtual void Configure(string name, TOptions options)
         {
             if (options == null)
@@ -293,6 +357,10 @@ public virtual void Configure(string name, TOptions options)
             }
         }
 
+        /// <summary>
+        /// Invoked to configure a TOptions instance with the <see cref="Options.DefaultName"/>.
+        /// </summary>
+        /// <param name="options">The options instance to configure.</param>
         public void Configure(TOptions options) => Configure(Options.DefaultName, options);
     }
 
@@ -344,17 +412,36 @@ public ConfigureNamedOptions(string name, TDep1 dependency1, TDep2 dependency2,
         /// </summary>
         public Action<TOptions, TDep1, TDep2, TDep3, TDep4, TDep5> Action { get; }
 
+        /// <summary>
+        /// The first dependency.
+        /// </summary>
         public TDep1 Dependency1 { get; }
 
+        /// <summary>
+        /// The second dependency.
+        /// </summary>
         public TDep2 Dependency2 { get; }
 
+        /// <summary>
+        /// The third dependency.
+        /// </summary>
         public TDep3 Dependency3 { get; }
 
+        /// <summary>
+        /// The fourth dependency.
+        /// </summary>
         public TDep4 Dependency4 { get; }
 
+        /// <summary>
+        /// The fifth dependency.
+        /// </summary>
         public TDep5 Dependency5 { get; }
 
-
+        /// <summary>
+        /// Invokes the registered configure Action if the name matches.
+        /// </summary>
+        /// <param name="name">The name of the options instance being configured.</param>
+        /// <param name="options">The options instance to configure.</param>
         public virtual void Configure(string name, TOptions options)
         {
             if (options == null)
@@ -369,7 +456,10 @@ public virtual void Configure(string name, TOptions options)
             }
         }
 
+        /// <summary>
+        /// Invoked to configure a TOptions instance with the <see cref="Options.DefaultName"/>.
+        /// </summary>
+        /// <param name="options">The options instance to configure.</param>
         public void Configure(TOptions options) => Configure(Options.DefaultName, options);
     }
-
 }
\ No newline at end of file
diff --git a/src/Microsoft.Extensions.Options/IOptions.cs b/src/Microsoft.Extensions.Options/IOptions.cs
index 2b1970383bc..81420a660e5 100644
--- a/src/Microsoft.Extensions.Options/IOptions.cs
+++ b/src/Microsoft.Extensions.Options/IOptions.cs
@@ -10,7 +10,7 @@ namespace Microsoft.Extensions.Options
     public interface IOptions<out TOptions> where TOptions : class, new()
     {
         /// <summary>
-        /// The default configured TOptions instance, equivalent to Get(string.Empty).
+        /// The default configured TOptions instance
         /// </summary>
         TOptions Value { get; }
     }
diff --git a/src/Microsoft.Extensions.Options/Microsoft.Extensions.Options.csproj b/src/Microsoft.Extensions.Options/Microsoft.Extensions.Options.csproj
index 71c6645449e..c513e455d83 100644
--- a/src/Microsoft.Extensions.Options/Microsoft.Extensions.Options.csproj
+++ b/src/Microsoft.Extensions.Options/Microsoft.Extensions.Options.csproj
@@ -3,7 +3,7 @@
   <PropertyGroup>
     <Description>Provides a strongly typed way of specifying and accessing settings using dependency injection.</Description>
     <TargetFramework>netstandard2.0</TargetFramework>
-    <NoWarn>$(NoWarn);CS1591</NoWarn>
+    <NoWarn>$(NoWarn)</NoWarn>
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
     <PackageTags>aspnetcore;options</PackageTags>
   </PropertyGroup>
@@ -11,6 +11,7 @@
   <ItemGroup>
     <PackageReference Include="Microsoft.Extensions.DependencyInjection.Abstractions" Version="$(MicrosoftExtensionsDependencyInjectionAbstractionsPackageVersion)" />
     <PackageReference Include="Microsoft.Extensions.Primitives" Version="$(MicrosoftExtensionsPrimitivesPackageVersion)" />
+    <PackageReference Include="System.ComponentModel.Annotations" Version="$(SystemComponentModelAnnotationsPackageVersion)" />
   </ItemGroup>
 
 </Project>
diff --git a/src/Microsoft.Extensions.Options/Options.cs b/src/Microsoft.Extensions.Options/Options.cs
index 1c33063c6a5..68d56be9d0d 100644
--- a/src/Microsoft.Extensions.Options/Options.cs
+++ b/src/Microsoft.Extensions.Options/Options.cs
@@ -8,6 +8,9 @@ namespace Microsoft.Extensions.Options
     /// </summary>
     public static class Options
     {
+        /// <summary>
+        /// The default name used for options instances: "".
+        /// </summary>
         public static readonly string DefaultName = string.Empty;
 
         /// <summary>
diff --git a/src/Microsoft.Extensions.Options/OptionsBuilder.cs b/src/Microsoft.Extensions.Options/OptionsBuilder.cs
index 771603a635b..c87b40e7d62 100644
--- a/src/Microsoft.Extensions.Options/OptionsBuilder.cs
+++ b/src/Microsoft.Extensions.Options/OptionsBuilder.cs
@@ -2,7 +2,6 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
-using System.Collections.Generic;
 using Microsoft.Extensions.DependencyInjection;
 
 namespace Microsoft.Extensions.Options
@@ -44,6 +43,7 @@ public OptionsBuilder(IServiceCollection services, string name)
         /// Note: These are run before all <seealso cref="PostConfigure(Action{TOptions})"/>.
         /// </summary>
         /// <param name="configureOptions">The action used to configure the options.</param>
+        /// <returns>The current OptionsBuilder.</returns>
         public virtual OptionsBuilder<TOptions> Configure(Action<TOptions> configureOptions)
         {
             if (configureOptions == null)
@@ -55,6 +55,13 @@ public virtual OptionsBuilder<TOptions> Configure(Action<TOptions> configureOpti
             return this;
         }
 
+        /// <summary>
+        /// Registers an action used to configure a particular type of options.
+        /// Note: These are run before all <seealso cref="PostConfigure(Action{TOptions})"/>.
+        /// </summary>
+        /// <typeparam name="TDep">A dependency used by the action.</typeparam>
+        /// <param name="configureOptions">The action used to configure the options.</param>
+        /// <returns>The current OptionsBuilder.</returns>
         public virtual OptionsBuilder<TOptions> Configure<TDep>(Action<TOptions, TDep> configureOptions)
             where TDep : class
         {
@@ -68,6 +75,14 @@ public virtual OptionsBuilder<TOptions> Configure<TDep>(Action<TOptions, TDep> c
             return this;
         }
 
+        /// <summary>
+        /// Registers an action used to configure a particular type of options.
+        /// Note: These are run before all <seealso cref="PostConfigure(Action{TOptions})"/>.
+        /// </summary>
+        /// <typeparam name="TDep1">The first dependency used by the action.</typeparam>
+        /// <typeparam name="TDep2">The second dependency used by the action.</typeparam>
+        /// <param name="configureOptions">The action used to configure the options.</param>
+        /// <returns>The current OptionsBuilder.</returns>
         public virtual OptionsBuilder<TOptions> Configure<TDep1, TDep2>(Action<TOptions, TDep1, TDep2> configureOptions)
             where TDep1 : class
             where TDep2 : class
@@ -82,6 +97,15 @@ public virtual OptionsBuilder<TOptions> Configure<TDep1, TDep2>(Action<TOptions,
             return this;
         }
 
+        /// <summary>
+        /// Registers an action used to configure a particular type of options.
+        /// Note: These are run before all <seealso cref="PostConfigure(Action{TOptions})"/>.
+        /// </summary>
+        /// <typeparam name="TDep1">The first dependency used by the action.</typeparam>
+        /// <typeparam name="TDep2">The second dependency used by the action.</typeparam>
+        /// <typeparam name="TDep3">The third dependency used by the action.</typeparam>
+        /// <param name="configureOptions">The action used to configure the options.</param>
+        /// <returns>The current OptionsBuilder.</returns>
         public virtual OptionsBuilder<TOptions> Configure<TDep1, TDep2, TDep3>(Action<TOptions, TDep1, TDep2, TDep3> configureOptions)
             where TDep1 : class
             where TDep2 : class
@@ -102,6 +126,16 @@ public virtual OptionsBuilder<TOptions> Configure<TDep1, TDep2, TDep3>(Action<TO
             return this;
         }
 
+        /// <summary>
+        /// Registers an action used to configure a particular type of options.
+        /// Note: These are run before all <seealso cref="PostConfigure(Action{TOptions})"/>.
+        /// </summary>
+        /// <typeparam name="TDep1">The first dependency used by the action.</typeparam>
+        /// <typeparam name="TDep2">The second dependency used by the action.</typeparam>
+        /// <typeparam name="TDep3">The third dependency used by the action.</typeparam>
+        /// <typeparam name="TDep4">The fourth dependency used by the action.</typeparam>
+        /// <param name="configureOptions">The action used to configure the options.</param>
+        /// <returns>The current OptionsBuilder.</returns>
         public virtual OptionsBuilder<TOptions> Configure<TDep1, TDep2, TDep3, TDep4>(Action<TOptions, TDep1, TDep2, TDep3, TDep4> configureOptions)
             where TDep1 : class
             where TDep2 : class
@@ -124,6 +158,17 @@ public virtual OptionsBuilder<TOptions> Configure<TDep1, TDep2, TDep3, TDep4>(Ac
             return this;
         }
 
+        /// <summary>
+        /// Registers an action used to configure a particular type of options.
+        /// Note: These are run before all <seealso cref="PostConfigure(Action{TOptions})"/>.
+        /// </summary>
+        /// <typeparam name="TDep1">The first dependency used by the action.</typeparam>
+        /// <typeparam name="TDep2">The second dependency used by the action.</typeparam>
+        /// <typeparam name="TDep3">The third dependency used by the action.</typeparam>
+        /// <typeparam name="TDep4">The fourth dependency used by the action.</typeparam>
+        /// <typeparam name="TDep5">The fifth dependency used by the action.</typeparam>
+        /// <param name="configureOptions">The action used to configure the options.</param>
+        /// <returns>The current OptionsBuilder.</returns>
         public virtual OptionsBuilder<TOptions> Configure<TDep1, TDep2, TDep3, TDep4, TDep5>(Action<TOptions, TDep1, TDep2, TDep3, TDep4, TDep5> configureOptions)
             where TDep1 : class
             where TDep2 : class
@@ -164,6 +209,13 @@ public virtual OptionsBuilder<TOptions> PostConfigure(Action<TOptions> configure
             return this;
         }
 
+        /// <summary>
+        /// Registers an action used to post configure a particular type of options.
+        /// Note: These are run before after <seealso cref="Configure(Action{TOptions})"/>.
+        /// </summary>
+        /// <typeparam name="TDep">The dependency used by the action.</typeparam>
+        /// <param name="configureOptions">The action used to configure the options.</param>
+        /// <returns>The current OptionsBuilder.</returns>
         public virtual OptionsBuilder<TOptions> PostConfigure<TDep>(Action<TOptions, TDep> configureOptions)
             where TDep : class
         {
@@ -177,6 +229,14 @@ public virtual OptionsBuilder<TOptions> PostConfigure<TDep>(Action<TOptions, TDe
             return this;
         }
 
+        /// <summary>
+        /// Registers an action used to post configure a particular type of options.
+        /// Note: These are run before after <seealso cref="Configure(Action{TOptions})"/>.
+        /// </summary>
+        /// <typeparam name="TDep1">The first dependency used by the action.</typeparam>
+        /// <typeparam name="TDep2">The second dependency used by the action.</typeparam>
+        /// <param name="configureOptions">The action used to configure the options.</param>
+        /// <returns>The current OptionsBuilder.</returns>
         public virtual OptionsBuilder<TOptions> PostConfigure<TDep1, TDep2>(Action<TOptions, TDep1, TDep2> configureOptions)
             where TDep1 : class
             where TDep2 : class
@@ -191,6 +251,15 @@ public virtual OptionsBuilder<TOptions> PostConfigure<TDep1, TDep2>(Action<TOpti
             return this;
         }
 
+        /// <summary>
+        /// Registers an action used to post configure a particular type of options.
+        /// Note: These are run before after <seealso cref="Configure(Action{TOptions})"/>.
+        /// </summary>
+        /// <typeparam name="TDep1">The first dependency used by the action.</typeparam>
+        /// <typeparam name="TDep2">The second dependency used by the action.</typeparam>
+        /// <typeparam name="TDep3">The third dependency used by the action.</typeparam>
+        /// <param name="configureOptions">The action used to configure the options.</param>
+        /// <returns>The current OptionsBuilder.</returns>
         public virtual OptionsBuilder<TOptions> PostConfigure<TDep1, TDep2, TDep3>(Action<TOptions, TDep1, TDep2, TDep3> configureOptions)
             where TDep1 : class
             where TDep2 : class
@@ -211,6 +280,16 @@ public virtual OptionsBuilder<TOptions> PostConfigure<TDep1, TDep2, TDep3>(Actio
             return this;
         }
 
+        /// <summary>
+        /// Registers an action used to post configure a particular type of options.
+        /// Note: These are run before after <seealso cref="Configure(Action{TOptions})"/>.
+        /// </summary>
+        /// <typeparam name="TDep1">The first dependency used by the action.</typeparam>
+        /// <typeparam name="TDep2">The second dependency used by the action.</typeparam>
+        /// <typeparam name="TDep3">The third dependency used by the action.</typeparam>
+        /// <typeparam name="TDep4">The fourth dependency used by the action.</typeparam>
+        /// <param name="configureOptions">The action used to configure the options.</param>
+        /// <returns>The current OptionsBuilder.</returns>
         public virtual OptionsBuilder<TOptions> PostConfigure<TDep1, TDep2, TDep3, TDep4>(Action<TOptions, TDep1, TDep2, TDep3, TDep4> configureOptions)
             where TDep1 : class
             where TDep2 : class
@@ -233,6 +312,17 @@ public virtual OptionsBuilder<TOptions> PostConfigure<TDep1, TDep2, TDep3, TDep4
             return this;
         }
 
+        /// <summary>
+        /// Registers an action used to post configure a particular type of options.
+        /// Note: These are run before after <seealso cref="Configure(Action{TOptions})"/>.
+        /// </summary>
+        /// <typeparam name="TDep1">The first dependency used by the action.</typeparam>
+        /// <typeparam name="TDep2">The second dependency used by the action.</typeparam>
+        /// <typeparam name="TDep3">The third dependency used by the action.</typeparam>
+        /// <typeparam name="TDep4">The fourth dependency used by the action.</typeparam>
+        /// <typeparam name="TDep5">The fifth dependency used by the action.</typeparam>
+        /// <param name="configureOptions">The action used to configure the options.</param>
+        /// <returns>The current OptionsBuilder.</returns>
         public virtual OptionsBuilder<TOptions> PostConfigure<TDep1, TDep2, TDep3, TDep4, TDep5>(Action<TOptions, TDep1, TDep2, TDep3, TDep4, TDep5> configureOptions)
             where TDep1 : class
             where TDep2 : class
@@ -257,9 +347,20 @@ public virtual OptionsBuilder<TOptions> PostConfigure<TDep1, TDep2, TDep3, TDep4
             return this;
         }
 
+        /// <summary>
+        /// Register a validation action for an options type using a default failure message..
+        /// </summary>
+        /// <param name="validation">The validation function.</param>
+        /// <returns>The current OptionsBuilder.</returns>
         public virtual OptionsBuilder<TOptions> Validate(Func<TOptions, bool> validation)
             => Validate(validation: validation, failureMessage: "A validation error has occured.");
 
+        /// <summary>
+        /// Register a validation action for an options type.
+        /// </summary>
+        /// <param name="validation">The validation function.</param>
+        /// <param name="failureMessage">The failure message to use when validation fails.</param>
+        /// <returns>The current OptionsBuilder.</returns>
         public virtual OptionsBuilder<TOptions> Validate(Func<TOptions, bool> validation, string failureMessage)
         {
             if (validation == null)
diff --git a/src/Microsoft.Extensions.Options/OptionsFactory.cs b/src/Microsoft.Extensions.Options/OptionsFactory.cs
index 6d8a79fef10..486ae8f9832 100644
--- a/src/Microsoft.Extensions.Options/OptionsFactory.cs
+++ b/src/Microsoft.Extensions.Options/OptionsFactory.cs
@@ -36,6 +36,9 @@ public OptionsFactory(IEnumerable<IConfigureOptions<TOptions>> setups, IEnumerab
             _validations = validations;
         }
 
+        /// <summary>
+        /// Returns a configured TOptions instance with the given name.
+        /// </summary>
         public TOptions Create(string name)
         {
             var options = new TOptions();
diff --git a/src/Microsoft.Extensions.Options/OptionsManager.cs b/src/Microsoft.Extensions.Options/OptionsManager.cs
index c1b2f09a4db..012438683c7 100644
--- a/src/Microsoft.Extensions.Options/OptionsManager.cs
+++ b/src/Microsoft.Extensions.Options/OptionsManager.cs
@@ -1,8 +1,6 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
-using System;
-
 namespace Microsoft.Extensions.Options
 {
     /// <summary>
@@ -23,6 +21,9 @@ public OptionsManager(IOptionsFactory<TOptions> factory)
             _factory = factory;
         }
 
+        /// <summary>
+        /// The default configured TOptions instance, equivalent to Get(Options.DefaultName).
+        /// </summary>
         public TOptions Value
         {
             get
@@ -31,6 +32,9 @@ public TOptions Value
             }
         }
 
+        /// <summary>
+        /// Returns a configured TOptions instance with the given name.
+        /// </summary>
         public virtual TOptions Get(string name)
         {
             name = name ?? Options.DefaultName;
diff --git a/src/Microsoft.Extensions.Options/OptionsMonitor.cs b/src/Microsoft.Extensions.Options/OptionsMonitor.cs
index dbd678df698..6d6d1387c2f 100644
--- a/src/Microsoft.Extensions.Options/OptionsMonitor.cs
+++ b/src/Microsoft.Extensions.Options/OptionsMonitor.cs
@@ -58,6 +58,9 @@ public TOptions CurrentValue
             get => Get(Options.DefaultName);
         }
 
+        /// <summary>
+        /// Returns a configured TOptions instance with the given name.
+        /// </summary>
         public virtual TOptions Get(string name)
         {
             name = name ?? Options.DefaultName;
diff --git a/src/Microsoft.Extensions.Options/OptionsValidationException.cs b/src/Microsoft.Extensions.Options/OptionsValidationException.cs
index 8d9f53f5757..a02f2886577 100644
--- a/src/Microsoft.Extensions.Options/OptionsValidationException.cs
+++ b/src/Microsoft.Extensions.Options/OptionsValidationException.cs
@@ -24,8 +24,14 @@ public OptionsValidationException(string optionsName, Type optionsType, IEnumera
             OptionsName = optionsName ?? throw new ArgumentNullException(nameof(optionsName));
         }
 
+        /// <summary>
+        /// The name of the options instance that failed.
+        /// </summary>
         public string OptionsName { get; }
 
+        /// <summary>
+        /// The type of the options that failed.
+        /// </summary>
         public Type OptionsType { get; }
 
         /// <summary>
diff --git a/src/Microsoft.Extensions.Options/PostConfigureOptions.cs b/src/Microsoft.Extensions.Options/PostConfigureOptions.cs
index fe261e95964..679b3527884 100644
--- a/src/Microsoft.Extensions.Options/PostConfigureOptions.cs
+++ b/src/Microsoft.Extensions.Options/PostConfigureOptions.cs
@@ -84,8 +84,16 @@ public PostConfigureOptions(string name, TDep dependency, Action<TOptions, TDep>
         /// </summary>
         public Action<TOptions, TDep> Action { get; }
 
+        /// <summary>
+        /// The dependency.
+        /// </summary>
         public TDep Dependency { get; }
 
+        /// <summary>
+        /// Invoked to configure a TOptions instance.
+        /// </summary>
+        /// <param name="name">The name of the options instance being configured.</param>
+        /// <param name="options">The options instance to configured.</param>
         public virtual void PostConfigure(string name, TOptions options)
         {
             if (options == null)
@@ -100,6 +108,10 @@ public virtual void PostConfigure(string name, TOptions options)
             }
         }
 
+        /// <summary>
+        /// Invoked to configure a TOptions instance using the <see cref="Options.DefaultName"/>.
+        /// </summary>
+        /// <param name="options">The options instance to configured.</param>
         public void PostConfigure(TOptions options) => PostConfigure(Options.DefaultName, options);
     }
 
@@ -139,10 +151,21 @@ public PostConfigureOptions(string name, TDep1 dependency, TDep2 dependency2, Ac
         /// </summary>
         public Action<TOptions, TDep1, TDep2> Action { get; }
 
+        /// <summary>
+        /// The first dependency.
+        /// </summary>
         public TDep1 Dependency1 { get; }
 
+        /// <summary>
+        /// The second dependency.
+        /// </summary>
         public TDep2 Dependency2 { get; }
 
+        /// <summary>
+        /// Invoked to configure a TOptions instance.
+        /// </summary>
+        /// <param name="name">The name of the options instance being configured.</param>
+        /// <param name="options">The options instance to configured.</param>
         public virtual void PostConfigure(string name, TOptions options)
         {
             if (options == null)
@@ -157,6 +180,10 @@ public virtual void PostConfigure(string name, TOptions options)
             }
         }
 
+        /// <summary>
+        /// Invoked to configure a TOptions instance using the <see cref="Options.DefaultName"/>.
+        /// </summary>
+        /// <param name="options">The options instance to configured.</param>
         public void PostConfigure(TOptions options) => PostConfigure(Options.DefaultName, options);
     }
 
@@ -200,13 +227,26 @@ public PostConfigureOptions(string name, TDep1 dependency, TDep2 dependency2, TD
         /// </summary>
         public Action<TOptions, TDep1, TDep2, TDep3> Action { get; }
 
+        /// <summary>
+        /// The first dependency.
+        /// </summary>
         public TDep1 Dependency1 { get; }
 
+        /// <summary>
+        /// The second dependency.
+        /// </summary>
         public TDep2 Dependency2 { get; }
 
+        /// <summary>
+        /// The third dependency.
+        /// </summary>
         public TDep3 Dependency3 { get; }
 
-
+        /// <summary>
+        /// Invoked to configure a TOptions instance.
+        /// </summary>
+        /// <param name="name">The name of the options instance being configured.</param>
+        /// <param name="options">The options instance to configured.</param>
         public virtual void PostConfigure(string name, TOptions options)
         {
             if (options == null)
@@ -221,6 +261,10 @@ public virtual void PostConfigure(string name, TOptions options)
             }
         }
 
+        /// <summary>
+        /// Invoked to configure a TOptions instance using the <see cref="Options.DefaultName"/>.
+        /// </summary>
+        /// <param name="options">The options instance to configured.</param>
         public void PostConfigure(TOptions options) => PostConfigure(Options.DefaultName, options);
     }
 
@@ -268,15 +312,31 @@ public PostConfigureOptions(string name, TDep1 dependency1, TDep2 dependency2, T
         /// </summary>
         public Action<TOptions, TDep1, TDep2, TDep3, TDep4> Action { get; }
 
+        /// <summary>
+        /// The first dependency.
+        /// </summary>
         public TDep1 Dependency1 { get; }
 
+        /// <summary>
+        /// The second dependency.
+        /// </summary>
         public TDep2 Dependency2 { get; }
 
+        /// <summary>
+        /// The third dependency.
+        /// </summary>
         public TDep3 Dependency3 { get; }
 
+        /// <summary>
+        /// The fourth dependency.
+        /// </summary>
         public TDep4 Dependency4 { get; }
 
-
+        /// <summary>
+        /// Invoked to configure a TOptions instance.
+        /// </summary>
+        /// <param name="name">The name of the options instance being configured.</param>
+        /// <param name="options">The options instance to configured.</param>
         public virtual void PostConfigure(string name, TOptions options)
         {
             if (options == null)
@@ -291,6 +351,10 @@ public virtual void PostConfigure(string name, TOptions options)
             }
         }
 
+        /// <summary>
+        /// Invoked to configure a TOptions instance using the <see cref="Options.DefaultName"/>.
+        /// </summary>
+        /// <param name="options">The options instance to configured.</param>
         public void PostConfigure(TOptions options) => PostConfigure(Options.DefaultName, options);
     }
 
@@ -342,17 +406,36 @@ public PostConfigureOptions(string name, TDep1 dependency1, TDep2 dependency2, T
         /// </summary>
         public Action<TOptions, TDep1, TDep2, TDep3, TDep4, TDep5> Action { get; }
 
+        /// <summary>
+        /// The first dependency.
+        /// </summary>
         public TDep1 Dependency1 { get; }
 
+        /// <summary>
+        /// The second dependency.
+        /// </summary>
         public TDep2 Dependency2 { get; }
 
+        /// <summary>
+        /// The third dependency.
+        /// </summary>
         public TDep3 Dependency3 { get; }
 
+        /// <summary>
+        /// The fourth dependency.
+        /// </summary>
         public TDep4 Dependency4 { get; }
 
+        /// <summary>
+        /// The fifth dependency.
+        /// </summary>
         public TDep5 Dependency5 { get; }
 
-
+        /// <summary>
+        /// Invoked to configure a TOptions instance.
+        /// </summary>
+        /// <param name="name">The name of the options instance being configured.</param>
+        /// <param name="options">The options instance to configured.</param>
         public virtual void PostConfigure(string name, TOptions options)
         {
             if (options == null)
@@ -367,6 +450,10 @@ public virtual void PostConfigure(string name, TOptions options)
             }
         }
 
+        /// <summary>
+        /// Invoked to configure a TOptions instance using the <see cref="Options.DefaultName"/>.
+        /// </summary>
+        /// <param name="options">The options instance to configured.</param>
         public void PostConfigure(TOptions options) => PostConfigure(Options.DefaultName, options);
     }
 
diff --git a/src/Microsoft.Extensions.Options/ValidateOptions.cs b/src/Microsoft.Extensions.Options/ValidateOptions.cs
index 0d8e5b63d0c..94be1dd9982 100644
--- a/src/Microsoft.Extensions.Options/ValidateOptions.cs
+++ b/src/Microsoft.Extensions.Options/ValidateOptions.cs
@@ -11,6 +11,12 @@ namespace Microsoft.Extensions.Options
     /// <typeparam name="TOptions">The instance being validated.</typeparam>
     public class ValidateOptions<TOptions> : IValidateOptions<TOptions> where TOptions : class
     {
+        /// <summary>
+        /// Constructor.
+        /// </summary>
+        /// <param name="name"></param>
+        /// <param name="validation"></param>
+        /// <param name="failureMessage"></param>
         public ValidateOptions(string name, Func<TOptions, bool> validation, string failureMessage)
         {
             Name = name;
@@ -33,6 +39,12 @@ public ValidateOptions(string name, Func<TOptions, bool> validation, string fail
         /// </summary>
         public string FailureMessage { get; }
 
+        /// <summary>
+        /// Validates a specific named options instance (or all when name is null).
+        /// </summary>
+        /// <param name="name">The name of the options instance being validated.</param>
+        /// <param name="options">The options instance.</param>
+        /// <returns>The <see cref="ValidateOptionsResult"/> result.</returns>
         public ValidateOptionsResult Validate(string name, TOptions options)
         {
             // Null name is used to configure all named options.
diff --git a/test/Microsoft.Extensions.Options.Test/Microsoft.Extensions.Options.Test.csproj b/test/Microsoft.Extensions.Options.Test/Microsoft.Extensions.Options.Test.csproj
index 2b82dd3f572..7c350060cdf 100644
--- a/test/Microsoft.Extensions.Options.Test/Microsoft.Extensions.Options.Test.csproj
+++ b/test/Microsoft.Extensions.Options.Test/Microsoft.Extensions.Options.Test.csproj
@@ -6,6 +6,7 @@
 
   <ItemGroup>
     <ProjectReference Include="..\..\src\Microsoft.Extensions.Options.ConfigurationExtensions\Microsoft.Extensions.Options.ConfigurationExtensions.csproj" />
+    <ProjectReference Include="..\..\src\Microsoft.Extensions.Options.DataAnnotations\Microsoft.Extensions.Options.DataAnnotations.csproj" />
   </ItemGroup>
 
   <ItemGroup>
diff --git a/test/Microsoft.Extensions.Options.Test/OptionsBuilderTest.cs b/test/Microsoft.Extensions.Options.Test/OptionsBuilderTest.cs
index 71b969895bc..23a15593a05 100644
--- a/test/Microsoft.Extensions.Options.Test/OptionsBuilderTest.cs
+++ b/test/Microsoft.Extensions.Options.Test/OptionsBuilderTest.cs
@@ -3,7 +3,9 @@
 
 using System;
 using System.Collections.Generic;
+using System.ComponentModel.DataAnnotations;
 using System.Linq;
+using System.Reflection;
 using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.DependencyInjection;
 using Xunit;
@@ -393,7 +395,7 @@ private void ValidateFailure<TOptions>(OptionsValidationException e, string name
             {
                 errors = new string[] { "A validation error has occured." };
             }
-            Assert.True(errors.SequenceEqual(e.Failures));
+            Assert.True(errors.SequenceEqual(e.Failures), "Expected: " + String.Join(" - ", e.Failures));
         }
 
         [Fact]
@@ -475,7 +477,8 @@ public void Validate()
                         try
                         {
                             getMethod.Invoke(monitor, new object[] { namedInstance });
-                        } catch (Exception e)
+                        }
+                        catch (Exception e)
                         {
                             if (e.InnerException is OptionsValidationException)
                             {
@@ -513,5 +516,105 @@ public void CanValidateOptionsEagerly()
             ValidateFailure<ComplexOptions>(error, Options.DefaultName, "A validation error has occured.", "Virtual", "Integer");
         }
 
+        [AttributeUsage(AttributeTargets.Field | AttributeTargets.Property, AllowMultiple = false, Inherited = true)]
+        public class FromAttribute : ValidationAttribute
+        {
+            public string Accepted { get; set; }
+
+            public override bool IsValid(object value)
+                => value == null || value.ToString() == Accepted;
+        }
+
+        [AttributeUsage(AttributeTargets.Field | AttributeTargets.Property, AllowMultiple = false, Inherited = true)]
+        public class DepValidator : ValidationAttribute
+        {
+            public string Target { get; set; }
+
+            protected override ValidationResult IsValid(object value, ValidationContext validationContext)
+            {
+                object instance = validationContext.ObjectInstance;
+                Type type = instance.GetType();
+                var dep1 = type.GetProperty("Dep1")?.GetValue(instance);
+                var dep2 = type.GetProperty(Target)?.GetValue(instance);
+                if (dep1 == dep2)
+                {
+                    return ValidationResult.Success;
+                }
+                return new ValidationResult("Dep1 != "+Target, new string[] { "Dep1", Target });
+            }
+        }
+
+        private class AnnotatedOptions
+        {
+            [Required]
+            public string Required { get; set; }
+
+            [StringLength(5, ErrorMessage = "Too long.")]
+            public string StringLength { get; set; }
+
+            [Range(-5, 5, ErrorMessage = "Out of range.")]
+            public int IntRange { get; set; }
+
+            [From(Accepted = "USA")]
+            public string Custom { get; set; }
+
+            [DepValidator(Target = "Dep2")]
+            public string Dep1 { get; set; }
+            public string Dep2 { get; set; }
+        }
+
+        [Fact]
+        public void CanValidateDataAnnotations()
+        {
+            var services = new ServiceCollection();
+            services.AddOptions<AnnotatedOptions>()
+                .Configure(o =>
+                {
+                    o.StringLength = "111111";
+                    o.IntRange = 10;
+                    o.Custom = "nowhere";
+                    o.Dep1 = "Not dep2";
+                })
+                .ValidateDataAnnotations();
+
+            var sp = services.BuildServiceProvider();
+
+            var error = Assert.Throws<OptionsValidationException>(() => sp.GetRequiredService<IOptions<AnnotatedOptions>>().Value);
+            ValidateFailure<AnnotatedOptions>(error, Options.DefaultName,
+                @"DataAnnotation validation failed for members Required with the error 'The Required field is required.'.
+DataAnnotation validation failed for members StringLength with the error 'Too long.'.
+DataAnnotation validation failed for members IntRange with the error 'Out of range.'.
+DataAnnotation validation failed for members Custom with the error 'The field Custom is invalid.'.
+DataAnnotation validation failed for members Dep1, Dep2 with the error 'Dep1 != Dep2'.");
+        }
+
+        [Fact]
+        public void CanValidateMixDataAnnotations()
+        {
+            var services = new ServiceCollection();
+            services.AddOptions<AnnotatedOptions>()
+                .Configure(o =>
+                {
+                    o.StringLength = "111111";
+                    o.IntRange = 10;
+                    o.Custom = "nowhere";
+                    o.Dep1 = "Not dep2";
+                })
+                .ValidateDataAnnotations()
+                .Validate(o => o.Custom != "nowhere", "I don't want to go to nowhere!");
+
+            var sp = services.BuildServiceProvider();
+
+            var error = Assert.Throws<OptionsValidationException>(() => sp.GetRequiredService<IOptions<AnnotatedOptions>>().Value);
+            ValidateFailure<AnnotatedOptions>(error, Options.DefaultName, 
+                @"DataAnnotation validation failed for members Required with the error 'The Required field is required.'.
+DataAnnotation validation failed for members StringLength with the error 'Too long.'.
+DataAnnotation validation failed for members IntRange with the error 'Out of range.'.
+DataAnnotation validation failed for members Custom with the error 'The field Custom is invalid.'.
+DataAnnotation validation failed for members Dep1, Dep2 with the error 'Dep1 != Dep2'.",
+                "I don't want to go to nowhere!");
+        }
+
+
     }
-} 
\ No newline at end of file
+}
\ No newline at end of file