// Reading XML Documentation at Run-Time// Bradley Smith - 2010/11/25using System;using System.Collections.Generic;using System.Linq;using System.Reflection;using System.Xml.Linq;using System.Xml.XPath;/// 
/// Provides extension methods for reading XML comments from reflected members./// 
public static class XmlDocumentationExtensions {    private static Dictionary
     
       cachedXml;    /// 
      
    /// Static constructor.    /// 
    static XmlDocumentationExtensions() {        cachedXml = new Dictionary
      
       (StringComparer.OrdinalIgnoreCase);    }    /// 
       
    /// Returns the expected name for a member element in the XML documentation file.    /// 
    /// 
       The reflected member.    /// 
       
        The name of the member element.
           private static string GetMemberElementName(MemberInfo member) {        char prefixCode;        string memberName = (member is Type)            ? ((Type)member).FullName                               // member is a Type            : (member.DeclaringType.FullName + "." + member.Name);  // member belongs to a Type        switch (member.MemberType) {            case MemberTypes.Constructor:                // XML documentation uses slightly different constructor names                memberName = memberName.Replace(".ctor", "#ctor");                goto case MemberTypes.Method;            case MemberTypes.Method:                prefixCode = 'M';                // parameters are listed according to their type, not their name                string paramTypesList = String.Join(                    ",",                    ((MethodBase)member).GetParameters()                        .Cast
       
        ()                        .Select(x => x.ParameterType.FullName                    ).ToArray()                );                if (!String.IsNullOrEmpty(paramTypesList)) memberName += "(" + paramTypesList + ")";                break;            case MemberTypes.Event:                prefixCode = 'E';                break;            case MemberTypes.Field:                prefixCode = 'F';                break;            case MemberTypes.NestedType:                // XML documentation uses slightly different nested type names                memberName = memberName.Replace('+', '.');                goto case MemberTypes.TypeInfo;            case MemberTypes.TypeInfo:                prefixCode = 'T';                break;            case MemberTypes.Property:                prefixCode = 'P';                break;            default:                throw new ArgumentException("Unknown member type", "member");        }        // elements are of the form "M:Namespace.Class.Method"        return String.Format("{0}:{1}", prefixCode, memberName);    }    /// 
        
    /// Returns the XML documentation (summary tag) for the specified member.    /// 
    /// 
        The reflected member.    /// 
        
         The contents of the summary tag for the member.
            public static string GetXmlDocumentation(this MemberInfo member) {        AssemblyName assemblyName = member.Module.Assembly.GetName();        return GetXmlDocumentation(member, assemblyName.Name + ".xml");    }        /// 
        
    /// Returns the XML documentation (summary tag) for the specified member.    /// 
    /// 
        The reflected member.    /// 
        Path to the XML documentation file.    /// 
        
         The contents of the summary tag for the member.
            public static string GetXmlDocumentation(this MemberInfo member, string pathToXmlFile) {        AssemblyName assemblyName = member.Module.Assembly.GetName();        XDocument xml = null;        if (cachedXml.ContainsKey(assemblyName.FullName))            xml = cachedXml[assemblyName.FullName];        else            cachedXml[assemblyName.FullName] = (xml = XDocument.Load(pathToXmlFile));        return GetXmlDocumentation(member, xml);    }    /// 
        
    /// Returns the XML documentation (summary tag) for the specified member.    /// 
    /// 
        The reflected member.    /// 
        XML documentation.    /// 
        
         The contents of the summary tag for the member.
            public static string GetXmlDocumentation(this MemberInfo member, XDocument xml) {        return xml.XPathEvaluate(            String.Format(                "string(/doc/members/member[@name='{0}']/summary)",                GetMemberElementName(member)            )        ).ToString().Trim();    }    /// 
        
    /// Returns the XML documentation (returns/param tag) for the specified parameter.    /// 
    /// 
        The reflected parameter (or return value).    /// 
        
         The contents of the returns/param tag for the parameter.
            public static string GetXmlDocumentation(this ParameterInfo parameter) {        AssemblyName assemblyName = parameter.Member.Module.Assembly.GetName();        return GetXmlDocumentation(parameter, assemblyName.Name + ".xml");    }    /// 
        
    /// Returns the XML documentation (returns/param tag) for the specified parameter.    /// 
    /// 
        The reflected parameter (or return value).    /// 
        Path to the XML documentation file.    /// 
        
         The contents of the returns/param tag for the parameter.
            public static string GetXmlDocumentation(this ParameterInfo parameter, string pathToXmlFile) {        AssemblyName assemblyName = parameter.Member.Module.Assembly.GetName();        XDocument xml = null;        if (cachedXml.ContainsKey(assemblyName.FullName))            xml = cachedXml[assemblyName.FullName];        else            cachedXml[assemblyName.FullName] = (xml = XDocument.Load(pathToXmlFile));        return GetXmlDocumentation(parameter, xml);    }    /// 
        
    /// Returns the XML documentation (returns/param tag) for the specified parameter.    /// 
    /// 
        The reflected parameter (or return value).    /// 
        XML documentation.    /// 
        
         The contents of the returns/param tag for the parameter.
            public static string GetXmlDocumentation(this ParameterInfo parameter, XDocument xml) {        if (parameter.IsRetval || String.IsNullOrEmpty(parameter.Name))            return xml.XPathEvaluate(                String.Format(                    "string(/doc/members/member[@name='{0}']/returns)",                    GetMemberElementName(parameter.Member)                )            ).ToString().Trim();        else            return xml.XPathEvaluate(                String.Format(                    "string(/doc/members/member[@name='{0}']/param[@name='{1}'])",                    GetMemberElementName(parameter.Member),                    parameter.Name                )            ).ToString().Trim();    }}