BackendlessService.cs

using BackendlessAPI;
using BackendlessAPI.RT.Data;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

namespace VoteMonitoryWebAssembly
{
    public class BackendlessService
    {
       
        public BackendlessService()
        {
            Backendless.InitApp("4C6B6C77-4DA2-610F-FF8C-E074D1084900", "26EA98E8-C559-4A18-8717-27FC1C4088A7");
        }    
    }
}

startup.cs

public void ConfigureServices(IServiceCollection services)
        {
            services.AddRazorPages();
            services.AddServerSideBlazor();
            services.AddSingleton<WeatherForecastService>();
            services.AddSingleton<BackendlessService>();
        }

sample razor page

@page "/counter"
@using BackendlessAPI;
@using BackendlessAPI.RT.Data;
@inject BackendlessService BS;
<h1>Counter</h1>

<p>Current count: @currentCount</p>

<button class="btn btn-primary" @onclick="IncrementCount">Click me</button>

<p>Current Object : @currentRegionObject</p>

@code {
    private int currentCount = 0;

    private void IncrementCount()
    {
        currentCount++;
    }


    private string currentRegionObject;
    private IEventHandler<Dictionary<String, Object>> regionTableRT;

    protected override void OnInitialized()
    {


        regionTableRT = Backendless.Data.Of("Region").RT();

        regionTableRT.AddCreateListener(createdObject =>
        {
            currentRegionObject = (string)createdObject["objectId"];
            Console.WriteLine($"an Order object has been updated in the database. Object ID - {createdObject["objectId"]}");
            StateHasChanged();
        });

    }
}