MethodInfoExtensions.cs

using System;
using System.Reflection;
using System.Text;

namespace DocGenerator
{
    public static class MethodInfoExtensions
    {
        /// <summary>
        /// Return the method signature as a string.
        /// </summary>
        /// <param name="method">The Method</param>
        /// <param name="callable">Return as an callable string(public void a(string b) would return a(b))</param>
        /// <returns>Method signature</returns>
        public static string GetSignature(this MethodInfo method, bool callable = false)
        {
            var firstParam = true;
            var sigBuilder = new StringBuilder();
            sigBuilder.Append(method.Name);

            // Add method generics
            if (method.IsGenericMethod)
            {
                sigBuilder.Append("<");
                foreach (var g in method.GetGenericArguments())
                {
                    if (firstParam)
                        firstParam = false;
                    else
                        sigBuilder.Append(", ");
                    sigBuilder.Append(TypeName(g));
                }
                sigBuilder.Append(">");
            }
            sigBuilder.Append("(");
            firstParam = true;
            var secondParam = false;
            foreach (var param in method.GetParameters())
            {
                if (firstParam)
                {
                    firstParam = false;
                    if (method.IsDefined(typeof(System.Runtime.CompilerServices.ExtensionAttribute), false))
                    {
                        if (callable)
                        {
                            secondParam = true;
                            continue;
                        }
                        sigBuilder.Append("this ");
                    }
                }
                else if (secondParam == true)
                    secondParam = false;
                else
                    sigBuilder.Append(", ");
                if (param.ParameterType.IsByRef)
                    sigBuilder.Append("ref ");
                else if (param.IsOut)
                    sigBuilder.Append("out ");
                if (!callable)
                {
                    sigBuilder.Append(TypeName(param.ParameterType));
                    sigBuilder.Append(' ');
                }
                sigBuilder.Append(param.Name);

                if (param.HasDefaultValue)
                {
                    object defaultValue;
                    if (param.ParameterType == typeof(bool))
                    {
                        defaultValue = (bool) param.DefaultValue ? "true" : "false";
                    }
                    else
                    {
                        defaultValue = param.DefaultValue;
                    }

                    sigBuilder.Append(" = " + defaultValue);
                }

            }
            sigBuilder.Append(")");
            return sigBuilder.ToString();
        }

        /// <summary>
        /// Get full type name with full namespace names
        /// </summary>
        /// <param name="type">Type. May be generic or nullable</param>
        /// <returns>Full type name, fully qualified namespaces</returns>
        public static string TypeName(Type type)
        {
            var nullableType = Nullable.GetUnderlyingType(type);
            if (nullableType != null)
                return nullableType.Name + "?";

            if (!type.IsGenericType)
                switch (type.Name)
                {
                    case "String": return "string";
                    case "Int32": return "int";
                    case "Decimal": return "decimal";
                    case "Object": return "object";
                    case "Void": return "void";
                    default:
                    {
                        return string.IsNullOrWhiteSpace(type.FullName) ? type.Name : type.FullName;
                    }
                }

            var sb = new StringBuilder(type.Name.Substring(0,
                type.Name.IndexOf('`'))
                );
            sb.Append('<');
            var first = true;
            foreach (var t in type.GetGenericArguments())
            {
                if (!first)
                    sb.Append(',');
                sb.Append(TypeName(t));
                first = false;
            }
            sb.Append('>');
            return sb.ToString();
        }

    }
}