Get Started with .NET SDK and Live Preview

using Contentstack.Core; // ContentstackClient
using Contentstack.Core.Models; // Stack, Query, Entry, Asset, ContentType
using Contentstack.Core.Configuration; // ContentstackOptions

{
  "ContentstackOptions": {
        "ApiKey": "<api_key>",
        "DeliveryToken": "<delivery_token>",
        "Environment": "<environment>",
        "LivePreview": {
	      "PreviewToken" : "<preview_token>",
	      "Enable" : true, 
	      "Host" : "rest-preview.contentstack.com" 
        }
    }
}

// Startup.cs
...
//Add following 
using Contentstack.Core;
using System.Linq;
using Microsoft.Extensions.Primitives;
public class Startup
{
    ...
    public void ConfigureServices(IServiceCollection services)
    {
        ...
        services.AddContentstack(Configuration); //Contentstack Configuration
    }
    // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
    public void Configure(IApplicationBuilder app, IHostingEnvironment env)
    {
        ...
        app.UseCors(x => x.AllowAnyHeader().AllowAnyMethod().AllowAnyOrigin()); //CORS to allow Contentstack origin
        app.Use(async (context, next) =>
        {
            var contentstackClient =  app.ApplicationServices.GetService<ContentstackClient>();
            var dict = context.Request.Query.Keys.Cast<string>().ToDictionary(k => k, v =>
                {
                    StringValues hash;
                    context.Request.Query.TryGetValue(v, out hash);
                    return hash.ToString();
                });
            try
            {
                await contentstackClient.LivePreviewQueryAsync(dict); 
            }
            catch { }
            await next.Invoke();
        });
    }
}

...
ContentstackLivePreview.init({
            enable: true,
            ssr: true,
            stackDetails: {
                apiKey: "API_KEY", //Stack API key
            },
        });
...

client.ContentType("CONTENT_TYPE_UID").Query().Find();
client.ContentType("CONTENT_TYPE_UID").Entry(“ENTRY_UID”).Find();