1.0 添加WEB API项目并按注释生成文档（多项目结构）

1.新建ASP.NET 项目，模板选择如图

2.选择Web API，并选择不进行身份验证方式

成功后我们看到这个结果。

至于其它三种身份验证方式，不太适合我的使用。而且这种方式也可以在代码里去实现身份验证，比较符合已有数据库的情况，这里不写。

3.给项目进行配置修改

3.1 修改对应项目生成路径。

这是单项目结构的，如果有多个项目并且有引用，把其它项目生成XML的地址改为接口项目的地址，当然也可以生成后再拷贝过去。

3.2修改WebAPITest\Areas\HelpPage\App_Start\HelpPageConfig.cs里面的代码。

反注释

 config.SetDocumentationProvider(new XmlDocumentationProvider(HttpContext.Current.Server.MapPath("~/App_Data/XmlDocument.xml")));

　　里面的文档改成我们上面生成的文档名称，打开help接口就能看到注释了。

如果是引用了多个项目，就麻烦点。

先把刚刚这句改一下

 config.SetDocumentationProvider(new XmlDocumentationProvider(
    HttpContext.Current.Server.MapPath("~/App_Data")));

　　看见XmlDocumentationProvider这个类没有？转到定义过去看看,下面是原来的代码，不用看了。

 /// <summary>
    /// A custom <see cref="IDocumentationProvider"/> that reads the API documentation from an XML documentation file.
    /// </summary>
    public class XmlDocumentationProvider : IDocumentationProvider, IModelDocumentationProvider
    {
        private XPathNavigator _documentNavigator;
        private const string TypeExpression = "/doc/members/member[@name='T:{0}']";
        private const string MethodExpression = "/doc/members/member[@name='M:{0}']";
        private const string PropertyExpression = "/doc/members/member[@name='P:{0}']";
        private const string FieldExpression = "/doc/members/member[@name='F:{0}']";
        private const string ParameterExpression = "param[@name='{0}']";

        /// <summary>
        /// Initializes a new instance of the <see cref="XmlDocumentationProvider"/> class.
        /// </summary>
        /// <param name="documentPath">The physical path to XML document.</param>
        public XmlDocumentationProvider(string documentPath)
        {
            if (documentPath == null)
            {
                throw new ArgumentNullException("documentPath");
            }
            XPathDocument xpath = new XPathDocument(documentPath);
            _documentNavigator = xpath.CreateNavigator();
        }

        public string GetDocumentation(HttpControllerDescriptor controllerDescriptor)
        {
            XPathNavigator typeNode = GetTypeNode(controllerDescriptor.ControllerType);
            return GetTagValue(typeNode, "summary");
        }

        public virtual string GetDocumentation(HttpActionDescriptor actionDescriptor)
        {
            XPathNavigator methodNode = GetMethodNode(actionDescriptor);
            return GetTagValue(methodNode, "summary");
        }

        public virtual string GetDocumentation(HttpParameterDescriptor parameterDescriptor)
        {
            ReflectedHttpParameterDescriptor reflectedParameterDescriptor = parameterDescriptor as ReflectedHttpParameterDescriptor;
            if (reflectedParameterDescriptor != null)
            {
                XPathNavigator methodNode = GetMethodNode(reflectedParameterDescriptor.ActionDescriptor);
                if (methodNode != null)
                {
                    string parameterName = reflectedParameterDescriptor.ParameterInfo.Name;
                    XPathNavigator parameterNode = methodNode.SelectSingleNode(String.Format(CultureInfo.InvariantCulture, ParameterExpression, parameterName));
                    if (parameterNode != null)
                    {
                        return parameterNode.Value.Trim();
                    }
                }
            }

            return null;
        }

        public string GetResponseDocumentation(HttpActionDescriptor actionDescriptor)
        {
            XPathNavigator methodNode = GetMethodNode(actionDescriptor);
            return GetTagValue(methodNode, "returns");
        }

        public string GetDocumentation(MemberInfo member)
        {
            string memberName = String.Format(CultureInfo.InvariantCulture, "{0}.{1}", GetTypeName(member.DeclaringType), member.Name);
            string expression = member.MemberType == MemberTypes.Field ? FieldExpression : PropertyExpression;
            string selectExpression = String.Format(CultureInfo.InvariantCulture, expression, memberName);
            XPathNavigator propertyNode = _documentNavigator.SelectSingleNode(selectExpression);
            return GetTagValue(propertyNode, "summary");
        }

        public string GetDocumentation(Type type)
        {
            XPathNavigator typeNode = GetTypeNode(type);
            return GetTagValue(typeNode, "summary");
        }

        private XPathNavigator GetMethodNode(HttpActionDescriptor actionDescriptor)
        {
            ReflectedHttpActionDescriptor reflectedActionDescriptor = actionDescriptor as ReflectedHttpActionDescriptor;
            if (reflectedActionDescriptor != null)
            {
                string selectExpression = String.Format(CultureInfo.InvariantCulture, MethodExpression, GetMemberName(reflectedActionDescriptor.MethodInfo));
                return _documentNavigator.SelectSingleNode(selectExpression);
            }

            return null;
        }

        private static string GetMemberName(MethodInfo method)
        {
            string name = String.Format(CultureInfo.InvariantCulture, "{0}.{1}", GetTypeName(method.DeclaringType), method.Name);
            ParameterInfo[] parameters = method.GetParameters();
            if (parameters.Length != )
            {
                string[] parameterTypeNames = parameters.Select(param => GetTypeName(param.ParameterType)).ToArray();
                name += String.Format(CultureInfo.InvariantCulture, "({0})", String.Join(",", parameterTypeNames));
            }

            return name;
        }

        private static string GetTagValue(XPathNavigator parentNode, string tagName)
        {
            if (parentNode != null)
            {
                XPathNavigator node = parentNode.SelectSingleNode(tagName);
                if (node != null)
                {
                    return node.Value.Trim();
                }
            }

            return null;
        }

        private XPathNavigator GetTypeNode(Type type)
        {
            string controllerTypeName = GetTypeName(type);
            string selectExpression = String.Format(CultureInfo.InvariantCulture, TypeExpression, controllerTypeName);
            return _documentNavigator.SelectSingleNode(selectExpression);
        }

        private static string GetTypeName(Type type)
        {
            string name = type.FullName;
            if (type.IsGenericType)
            {
                // Format the generic type name to something like: Generic{System.Int32,System.String}
                Type genericType = type.GetGenericTypeDefinition();
                Type[] genericArguments = type.GetGenericArguments();
                string genericTypeName = genericType.FullName;

                // Trim the generic parameter counts from the name
                genericTypeName = genericTypeName.Substring(, genericTypeName.IndexOf('`'));
                string[] argumentTypeNames = genericArguments.Select(t => GetTypeName(t)).ToArray();
                name = String.Format(CultureInfo.InvariantCulture, "{0}{{{1}}}", genericTypeName, String.Join(",", argumentTypeNames));
            }
            if (type.IsNested)
            {
                // Changing the nested type name from OuterType+InnerType to OuterType.InnerType to match the XML documentation syntax.
                name = name.Replace("+", ".");
            }

            return name;
        }
    }

　　我们把它改下，整个类替换掉，没引用的自己右键引用。

 public class XmlDocumentationProvider : IDocumentationProvider, IModelDocumentationProvider
    {
        // private XPathNavigator _documentNavigator;
        private List<XPathNavigator> _documentNavigators = new List<XPathNavigator>();
        private const string TypeExpression = "/doc/members/member[@name='T:{0}']";
        private const string MethodExpression = "/doc/members/member[@name='M:{0}']";
        private const string PropertyExpression = "/doc/members/member[@name='P:{0}']";
        private const string FieldExpression = "/doc/members/member[@name='F:{0}']";
        private const string ParameterExpression = "param[@name='{0}']";

        /// <summary>
        /// Initializes a new instance of the <see cref="XmlDocumentationProvider"/> class.
        /// </summary>
        /// <param name="documentPath">The physical path to XML document.</param>
        //public XmlDocumentationProvider(string documentPath)
        //{
        //    if (documentPath == null)
        //    {
        //        throw new ArgumentNullException("documentPath");
        //    }
        //    XPathDocument xpath = new XPathDocument(documentPath);
        //    _documentNavigator = xpath.CreateNavigator();
        //}
        /// <summary>
        /// Initializes a new instance of the <see cref="XmlDocumentationProvider"/> class.
        /// </summary>
        /// <param name="appDataPath">The physical path to XML document.</param>
        public XmlDocumentationProvider(string appDataPath)
        {
            if (appDataPath == null)
            {
                throw new ArgumentNullException("appDataPath");
            }

            var files = new[] { "AuthSystem.xml", "AuthSystem.SQL.xml", "AuthSystem.Common.XML" };//这里是你其它dll的说明路径，自己可以改写。例如 var files = Directory.GetFiles(appDataPath, "TLSC.*.xml");//获取所有类似的xml
            foreach (var file in files)
            {
                XPathDocument xpath = new XPathDocument(Path.Combine(appDataPath, file));
                _documentNavigators.Add(xpath.CreateNavigator());
            }
        }

        private XPathNavigator SelectSingleNode(string selectExpression)
        {
            foreach (var navigator in _documentNavigators)
            {
                var propertyNode = navigator.SelectSingleNode(selectExpression);
                if (propertyNode != null)
                    return propertyNode;
            }
            return null;
        }
        public string GetDocumentation(HttpControllerDescriptor controllerDescriptor)
        {
            XPathNavigator typeNode = GetTypeNode(controllerDescriptor.ControllerType);
            return GetTagValue(typeNode, "summary");
        }

        public virtual string GetDocumentation(HttpActionDescriptor actionDescriptor)
        {
            XPathNavigator methodNode = GetMethodNode(actionDescriptor);
            return GetTagValue(methodNode, "summary");
        }

        public virtual string GetDocumentation(HttpParameterDescriptor parameterDescriptor)
        {
            ReflectedHttpParameterDescriptor reflectedParameterDescriptor = parameterDescriptor as ReflectedHttpParameterDescriptor;
            if (reflectedParameterDescriptor != null)
            {
                XPathNavigator methodNode = GetMethodNode(reflectedParameterDescriptor.ActionDescriptor);
                if (methodNode != null)
                {
                    string parameterName = reflectedParameterDescriptor.ParameterInfo.Name;
                    XPathNavigator parameterNode = methodNode.SelectSingleNode(String.Format(CultureInfo.InvariantCulture, ParameterExpression, parameterName));
                    if (parameterNode != null)
                    {
                        return parameterNode.Value.Trim();
                    }
                }
            }

            return null;
        }

        public string GetResponseDocumentation(HttpActionDescriptor actionDescriptor)
        {
            XPathNavigator methodNode = GetMethodNode(actionDescriptor);
            return GetTagValue(methodNode, "returns");
        }

        public string GetDocumentation(MemberInfo member)
        {
            string memberName = String.Format(CultureInfo.InvariantCulture, "{0}.{1}", GetTypeName(member.DeclaringType), member.Name);
            string expression = member.MemberType == MemberTypes.Field ? FieldExpression : PropertyExpression;
            string selectExpression = String.Format(CultureInfo.InvariantCulture, expression, memberName);
            XPathNavigator propertyNode = SelectSingleNode(selectExpression);
            return GetTagValue(propertyNode, "summary");
        }

        public string GetDocumentation(Type type)
        {
            XPathNavigator typeNode = GetTypeNode(type);
            return GetTagValue(typeNode, "summary");
        }

        private XPathNavigator GetMethodNode(HttpActionDescriptor actionDescriptor)
        {
            ReflectedHttpActionDescriptor reflectedActionDescriptor = actionDescriptor as ReflectedHttpActionDescriptor;
            if (reflectedActionDescriptor != null)
            {
                string selectExpression = String.Format(CultureInfo.InvariantCulture, MethodExpression, GetMemberName(reflectedActionDescriptor.MethodInfo));
                return SelectSingleNode(selectExpression);
            }

            return null;
        }

        private static string GetMemberName(MethodInfo method)
        {
            string name = String.Format(CultureInfo.InvariantCulture, "{0}.{1}", GetTypeName(method.DeclaringType), method.Name);
            ParameterInfo[] parameters = method.GetParameters();
            if (parameters.Length != )
            {
                string[] parameterTypeNames = parameters.Select(param => GetTypeName(param.ParameterType)).ToArray();
                name += String.Format(CultureInfo.InvariantCulture, "({0})", String.Join(",", parameterTypeNames));
            }

            return name;
        }

        private static string GetTagValue(XPathNavigator parentNode, string tagName)
        {
            if (parentNode != null)
            {
                XPathNavigator node = parentNode.SelectSingleNode(tagName);
                if (node != null)
                {
                    return node.Value.Trim();
                }
            }

            return null;
        }

        private XPathNavigator GetTypeNode(Type type)
        {
            string controllerTypeName = GetTypeName(type);
            string selectExpression = String.Format(CultureInfo.InvariantCulture, TypeExpression, controllerTypeName);
            return SelectSingleNode(selectExpression);
        }

        private static string GetTypeName(Type type)
        {
            string name = type.FullName;
            if (type.IsGenericType)
            {
                // Format the generic type name to something like: Generic{System.Int32,System.String}
                Type genericType = type.GetGenericTypeDefinition();
                Type[] genericArguments = type.GetGenericArguments();
                string genericTypeName = genericType.FullName;

                // Trim the generic parameter counts from the name
                genericTypeName = genericTypeName.Substring(, genericTypeName.IndexOf('`'));
                string[] argumentTypeNames = genericArguments.Select(t => GetTypeName(t)).ToArray();
                name = String.Format(CultureInfo.InvariantCulture, "{0}{{{1}}}", genericTypeName, String.Join(",", argumentTypeNames));
            }
            if (type.IsNested)
            {
                // Changing the nested type name from OuterType+InnerType to OuterType.InnerType to match the XML documentation syntax.
                name = name.Replace("+", ".");
            }

            return name;
        }
    }

原理就是从只读一个文档改成读取多个文档。这样就能在help中看到我们写的注释（summary）了。

效果图就不贴了，免得浪费大家流量哈哈。