webapi help 多XML设置

webapi help具体配置这里不做太多介绍。一般情况下项目都会分层，webapi help 官方给出的实例是在同一个项目下。

如何支持多个项目呢？

1.在HelpPage下增加 MultiXmlDocumentationProvider.cs文件

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.修改/HelpPage/App_Start/HelpPageConfig.cs，原先的不用使用。

config.SetDocumentationProvider(new MultiXmlDocumentationProvider(HttpContext.Current.Server.MapPath("~/Areas/HelpPage/Model.XML"), HttpContext.Current.Server.MapPath("~/Areas/HelpPage/WebApiHelp.XML")));