我们可以很清楚的看到，返回的`AlarmRecodrdDto`并没有注释文档啊！可是我已经在类库的中写过了该代码的注释的。为毛就没有呢？？？

其实啊，我们的注释文档是自动生成xml文件，再由HelpPage来读取该xml中的注释信息，最后展示在页面上。那些没有注释的文档是由于我们的代码注释没有生成对应的注释xml文件，所以就没法读取啦！！！

using System;

using System.Linq;

using System.Reflection;

using System.Web.Http.Controllers;

using System.Web.Http.Description;

using GTCASP.Website.Areas.HelpPage.ModelDescriptions;

namespace GTCASP.Website.Areas.HelpPage.Models

{

    /// <summary>A custom

    /// <see cref="IDocumentationProvider"/>

    /// that reads the API documentation from a collection of XML documentation files.

    /// </summary>

    public class MultiXmlDocumentationProvider : IDocumentationProvider, IModelDocumentationProvider

    {

        /*********

    ** Properties

    *********/

        /// <summary>The internal documentation providers for specific files.</summary>

        private readonly XmlDocumentationProvider[] Providers;

        /*********

        ** Public methods

        *********/

        /// <summary>Construct an instance.</summary>

        /// <param name="paths">The physical paths to the XML documents.</param>

        public MultiXmlDocumentationProvider(params string[] paths)

        {

            this.Providers = paths.Select(p => new XmlDocumentationProvider(p)).ToArray();

        }

        /// <summary>Gets the documentation for a subject.</summary>

        /// <param name="subject">The subject to document.</param>

        public string GetDocumentation(MemberInfo subject)

        {

            return this.GetFirstMatch(p => p.GetDocumentation(subject));

        }

        /// <summary>Gets the documentation for a subject.</summary>

        /// <param name="subject">The subject to document.</param>

        public string GetDocumentation(Type subject)

        {

            return this.GetFirstMatch(p => p.GetDocumentation(subject));

        }

        /// <summary>Gets the documentation for a subject.</summary>

        /// <param name="subject">The subject to document.</param>

        public string GetDocumentation(HttpControllerDescriptor subject)

        {

            return this.GetFirstMatch(p => p.GetDocumentation(subject));

        }

        /// <summary>Gets the documentation for a subject.</summary>

        /// <param name="subject">The subject to document.</param>

        public string GetDocumentation(HttpActionDescriptor subject)

        {

            return this.GetFirstMatch(p => p.GetDocumentation(subject));

        }

        /// <summary>Gets the documentation for a subject.</summary>

        /// <param name="subject">The subject to document.</param>

        public string GetDocumentation(HttpParameterDescriptor subject)

        {

            return this.GetFirstMatch(p => p.GetDocumentation(subject));

        }

        /// <summary>Gets the documentation for a subject.</summary>

        /// <param name="subject">The subject to document.</param>

        public string GetResponseDocumentation(HttpActionDescriptor subject)

        {

            return this.GetFirstMatch(p => p.GetDocumentation(subject));

        }

        /*********

        ** Private methods

        *********/

        /// <summary>Get the first valid result from the collection of XML documentation providers.</summary>

        /// <param name="expr">The method to invoke.</param>

        private string GetFirstMatch(Func<XmlDocumentationProvider, string> expr)

        {

            return this.Providers

                .Select(expr)

                .FirstOrDefault(p => !String.IsNullOrWhiteSpace(p));

        }

    }

}