Program.cs

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Runtime.CompilerServices;
using System.Text;
using System.Text.Json;
using System.Xml;
using System.Xml.Linq;
using System.Xml.Serialization;

namespace DUMPBINPARSER
{
    public class Program
    {
        public class KnownApis
        {
            public KnownApi[] Apis { get; set; }
        }

        public class Person
        {
            public string Name { get; set; }
            public int Alter { get; set; }
        }

        [Serializable]
        public class KnownApi
        {
            public string Dll { get; set; }
            public string[] Methods { get; set; }
        }

        private static XDocument CreateXmlFromObjects(string rootElementName, params object[] inputs)
        {
            var doc = new XDocument();
            using (XmlWriter writer = doc.CreateWriter())
            {
                writer.WriteStartElement(rootElementName);
                foreach (var input in inputs)
                    new XmlSerializer(input.GetType()).Serialize(writer, input);
                writer.WriteEndElement();
            }

            return doc;
        }

        static List<string> GetDumpbinOutput(string filepath)
        {
            var pi = new ProcessStartInfo(@"C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\VC\Tools\MSVC\14.27.29110\bin\Hostx86\x86\dumpbin.exe", $"/EXPORTS {filepath}");
            pi.RedirectStandardOutput = true;
            var newPRoc = Process.Start(pi);
            List<string> lines = new List<string>();
            while (!newPRoc.StandardOutput.EndOfStream)
            {
                string line = newPRoc.StandardOutput.ReadLine();
                lines.Add(line);
            }
            newPRoc.WaitForExit();
            return lines;
        }

        static void Main()
        {
            var files = Directory.EnumerateFiles(@"C:\Windows\System32", "*.dll").ToArray();

            var dict = new Dictionary<string, HashSet<string>>();
            var file = files.AsParallel().Select(ParseDumpbin).Where(x => x.methods.Any()).Select(xy => new KnownApi() { Dll = Path.GetFileName(xy.dll), Methods = xy.methods }).ToArray();
            var ms = new MemoryStream();
            System.Xml.Serialization.XmlSerializer x = new System.Xml.Serialization.XmlSerializer(file.First().GetType().MakeArrayType());

            //var xml = CreateXmlFromObjects("KnownApi", files.Cast<Object>().ToArray());
            var ct = file.SelectMany(xx => xx.Methods).Count();
            x.Serialize(ms, file);
            var json = JsonSerializer.Serialize<KnownApi[]>(file);
            KnownApi[] knownApis = JsonSerializer.Deserialize<KnownApi[]>(json);
            File.WriteAllText(@"D:\Repos\Serilized.txt", Encoding.UTF8.GetString(ms.ToArray()));
            Console.ReadKey();
        }

        /*
            var serializer = new XmlSerializer(typeof(KnownApi).MakeArrayType());
            var str = GeneratorResources.ResourceManager.GetString("DllImportExactNamingGeneratorResource", CultureInfo.InvariantCulture);

            var json = (serializer.Deserialize(XmlReader.Create(new StringReader(str))) as KnownApi[])!;*/

        static (string dll, string[] methods) ParseDumpbin(string file)
        {
            var lines = (GetDumpbinOutput(file));
            var dll = lines.Single(x => x.StartsWith("Dump of file "));
            var indexOfDll = lines.IndexOf(dll);
            dll = dll.Substring(dll.LastIndexOf("\\"));
            var methods = lines
                .SkipWhile(l => !l.StartsWith("    ordinal hint RVA      name"))
                .Skip(2)
                .Where(x => x.Length > 27)
                .Select(x => x.Substring(26).Trim())
                .Where(x => !x.Equals("[NONAME]"))
                .Select(x => x.Contains(' ') ? x.Substring(0, x.IndexOf(' ')) : x).ToArray();
            var newLines = methods.ToHashSet(); //l.EndsWith("W") && newLines.Contains(l.Substring(0, l.Length - 1) + "A") && !newLines.Contains(l.Substring(0, l.Length - 1))
            methods = methods.Where(l => !l.Contains("?")).ToArray();
            return (dll, methods);
        }
    }
}