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TickersComponent

BidAskComponent3

@page "/"

@using BlazorFiddleProject;

<button @onclick="changeJustOne">Make a change to just the first data-piece</button>

<div>
    <TickersComponent dataPieces="dataPieces" />
</div>

@code
{
    public List<DataPiece> dataPieces;

    protected override void OnInitialized()
    {
        Console.WriteLine("OnInitialized on index.razor");
        dataPieces = new List<DataPiece>();
       
        for (int i = 0; i < 200; i++)
            dataPieces.Add(new DataPiece { Id = i.ToString(), Bid = 1f, Ask = 2f });

        base.OnInitialized();
    }


    public void changeJustOne()
    {
        dataPieces.First().Bid = 3f;
        Console.WriteLine("Added...");
    }

}

namespace BlazorFiddleProject
{
    using Microsoft.AspNetCore.Components.Builder;
    using Microsoft.Extensions.DependencyInjection;
    using System;
    using System.Collections.Generic;
    using System.Reflection;
    using System.Linq;

    public class DataPiece
    {
        public string Id { get; set; }
        public double Bid { get; set; } 
        public double Ask { get; set; }
    }

    public class Startup
    {
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddSingleton<DataPieceAccess>();
        }

        public void Configure(IComponentsApplicationBuilder app)
        {
            app.AddComponent<App>("app");
        }
    }

    public class DataPieceAccess
    {
        public IDictionary<string, DataPiece> DataPieceById { get; } = new Dictionary<string, DataPiece>();
    } 

    public static class ReflectionHelper
    {
        public static IDictionary<string, object> ChildProperties<T>(T obj)
        {
            var type = typeof(T);
            var properties = type
                .GetProperties()
                .Select(p => (p.Name, Value: p.GetValue(obj)));

            return properties.ToDictionary(tuple => tuple.Name, tuple => tuple.Value);
        }
        
        public static IDictionary<string, object> TrackChangeProperties<T>(T obj, Type componentType)
        {
            var type = typeof(T);
            var namesToTrack = TrackChangePropertyNames<T>(componentType);
            var properties = type
                .GetProperties()
                .Where(p => namesToTrack.Contains(p.Name))
                .Select(p => (p.Name, Value: p.GetValue(obj)));

            return properties.ToDictionary(tuple => tuple.Name, tuple => tuple.Value);
        }

        private static IEnumerable<string> TrackChangePropertyNames<T>(Type componentType)
        {
            var sourceParameterTypeName = typeof(T).Name;
            var namesDefinedOnClass = componentType
                .GetCustomAttributes<TrackChangeAttribute>()
                .Where(tc => sourceParameterTypeName == tc.ParameterTypeName)
                .Select(tc => tc.ChildPropertyName);
            var namesDefinedOnProperties = componentType
                .GetProperties()
                .SelectMany(p => p.GetCustomAttributes<TrackChangeAttribute>()
                    .Where(tc => sourceParameterTypeName == tc.ParameterTypeName)
                    .Select(tc => tc.ChildPropertyName));

            return namesDefinedOnClass.Concat(namesDefinedOnProperties).Distinct();
        }
    }

    [AttributeUsage(AttributeTargets.Property | AttributeTargets.Class, AllowMultiple = true, Inherited = true)]
    public class TrackChangeAttribute : Attribute
    {
        public TrackChangeAttribute(string parameterTypeName, string childPropertyName)
        {
            ParameterTypeName = parameterTypeName;
            ChildPropertyName = childPropertyName;
        }

        public string ParameterTypeName { get; }
        public string ChildPropertyName { get; }
    }
}

<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8"/>
    <meta name="viewport" content="width=device-width">
    <title>BlazorFiddleProject</title>
    <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css" integrity="sha384-ggOyR0iXCbMQv3Xipma34MD+dH/1fQ784/j6cY/iJTQUOhcWr7x9JvoRxT2MZw1T" crossorigin="anonymous">

    <style>
        app { }
    </style>

    <script type="text/javascript">
    </script>
</head>
<body>
<app>Loading...</app>

<script src="_framework/blazor.webassembly.js"></script>
<script src="https://code.jquery.com/jquery-3.3.1.slim.min.js" integrity="sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo" crossorigin="anonymous"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.7/umd/popper.min.js" integrity="sha384-UO2eT0CpHqdSJQ6hJty5KVphtPhzWj9WO1clHTMGa3JDZwrnQq4sF86dIHNDz0W1" crossorigin="anonymous"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/js/bootstrap.min.js" integrity="sha384-JjSmVgyd0p3pXB1rRibZUAYoIIy6OrQ6VrjIEaFf/nJGzIxFDsf4x0xIM+B07jRM" crossorigin="anonymous"></script>
</body>
</html>

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