using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.IO;

using System.Diagnostics;

using System.Collections.ObjectModel;

using System.Runtime.Serialization;

using System.Xml;

​

using ProtoBuf.Meta;

using ProtoBuf;

​

using System.Globalization;

using System.Threading;

​

using System.ComponentModel;

​

// https://stackoverflow.com/questions/41622916/deserialize-binary-data-of-object-array-as-elements-are-available

​

​

​

    [ProtoContract]

    public class Person

    {

        [ProtoMember(1)]

        public long Id { get; set; }

        public override string ToString()

        {

            return string.Format("{0}: Id = {1}", base.ToString(), Id);

        }

    }

​

    [ProtoContract]

    public class RootObject

    {

        public RootObject()

        {

            this.People = new ObservableCollection<Person>();

        }

​

        [ProtoMember(1)]

        public ObservableCollection<Person> People { get; private set; }

​

        public event EventHandler<EventArgs<StreamingContext>> OnDeserialized;

​

        [OnDeserialized]

        internal void OnDeserializedMethod(StreamingContext context)

        {

            var onDeserialized = OnDeserialized;

            if (onDeserialized != null)

                onDeserialized(this, new EventArgs<StreamingContext> { Value = context });

        }

    }

​

    public class EventArgs<T> : EventArgs

    {

        public T Value { get; set; }

    }

​

    class TestClass

    {

        Stream stream;

        const int Length = 10001;

​

        public void Test()

        {

            var root = new RootObject();

            foreach (var person in Enumerable.Range(0, Length).Select(i => new Person { Id = i }))

                root.People.Add(person);

​

            stream = new MemoryStream();

            Serializer.Serialize(stream, root);

            stream.Position = 0;

​

            // Allocate a new RootObject

            var newRoot = new RootObject();

​

            // Add listeners to process chunks of Person objects as they are added

            newRoot.People.CollectionChanged += (o, e) =>

                {

                    // Process each chunk of 5000.

                    var collection = (ICollection<Person>)o;

                    ProcessItems(collection, false);

                };

​

            newRoot.OnDeserialized += (o, e) =>

                {

                    // Forcibly process any remaining no matter how many.

                    ProcessItems(((RootObject)o).People, true);

                };

​

            // Deserialize from the stream onto the pre-allocated newRoot

            Serializer.Merge(stream, newRoot);

​

            Console.WriteLine("Done");

        }

​

        const int ProcessIncrement = 50; // Change to 5000 in production.

        void ProcessItems(ICollection<Person> people, bool force)

        {

            if (people == null || people.Count == 0)

                return;

            if (people.Count >= ProcessIncrement || force)

            {

                // Remove and process the items, possibly on a different thread.

                Console.WriteLine(string.Format("Processing {0} people. first = \"{1}\", last = \"{2}\", stream.Position = {3}", 

                                                people.Count, people.First(), people.Last(), stream.Position));

                people.Clear();

            }

        }

    }

​

​

    public class Program

    {

        public static void Main()

        {

            Console.WriteLine("protobuf-net version: " + typeof(ProtoBuf.Serializer).Assembly.FullName + "\n");

            ProtoBuf.Meta.RuntimeTypeModel.Default.AutoCompile = false; // Required for security purposes on dotnetfiddle

            new TestClass().Test();

        }

    }