咱们新建webapi项目时，默认会生成HelpPage，里面会有api的详细说明，但默认类只能加载当前项目的xml文件，其他项目中的字段说明就没法显示了，如何解决？往下看

1. 咱们首先新建一个支持加载多xml的类 MultiXmlDocumentationProvider ，

/// <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));
        }
    }

2.找到HelpPageConfig，vs可以搜索到

在Register方法中添加如下代码

config.SetDocumentationProvider(new MultiXmlDocumentationProvider(
                HttpContext.Current.Server.MapPath("~/App_Data/ZhongXin.ZXWX.WebApi.xml"),
                HttpContext.Current.Server.MapPath("~/App_Data/ZhongXin.ZXWX.Model.xml"),
                HttpContext.Current.Server.MapPath("~/App_Data/ZhongXin.ZXWX.Common.xml")
                ));

OK，运行起来吧

注意事项：xml文件要看看是否生成了

.网上有说要在HelpPageConfig中注释掉一下代码，试过没注释也没问题

#region *************************默认JSON显示接口***************************************
            //config.SetSampleForMediaType(
            //    new TextSample("Binary JSON content. See http://bsonspec.org for details."),
            //    new MediaTypeHeaderValue("application/bson"));
            #endregion

 

另外也可以使用swagger生成API文档，可在Nuget下载