ASP.NET Core disable authentication in development environment

    You can bypass authorization in development environment by applying AllowAnonymousAttribute() to your endpoints. as below code 

 public void Configure(IApplicationBuilder app, IWebHostEnvironment env)

        {

           //-----------------------

            app.UseRouting();

            app.UseEndpoints(endpoints =>

            {

                if (env.IsDevelopment())

                    endpoints.MapControllers().WithMetadata(

                        new AllowAnonymousAttribute());

                else

                    endpoints.MapControllers();

            });

        //---------------------------

          }

How to Get the Current User in ASP.NET Core

 Create new Controller and add below code:

using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
namespace Dotnet_Core_MVC.Controllers
{
    public class ExpHttpContextAccessorController : Controller
    {
        private readonly IHttpContextAccessor _httpContextAccessor = new HttpContextAccessor();
        public IActionResult Index()
        {
            string userName = _httpContextAccessor.HttpContext.User.Identity.Name;
            ViewBag.userName = userName;
            return View();
        }
    }
}

Go to View and add below code:

 <b>Welcome:@ViewBag.userName</b>

Update ConfigureServices() in Startup.cs as below:

 public void ConfigureServices(IServiceCollection services)

        {

            services.AddControllersWithViews();

            services.AddHttpContextAccessor(); 

        }

How to use ViewBag inside of Filters of Asp.net Core

 Create ViewBag in Action Filter as below: 

using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.Filters;
using System;
namespace Dotnet_Core_MVC.CustomActionFilters
{
    public class CustomActionFilter : Attribute, IActionFilter
    {
        public void OnActionExecuted(ActionExecutedContext context)
        {
            if (context.Controller is Controller controller1)
            {
                controller1.ViewBag.MyName = "Adi";
            }
        }
        public void OnActionExecuting(ActionExecutingContext context)
        {
           
        }
    }
}

Use ViewBag in your View Pages as Below:

 <b>Welcome:@ViewBag.MyName</b>

How to Add Custom header at IAction method in Asp.net Core

 [HttpGet]

[Route("GetStudents")]

public IActionResult GetAllStudents()

{

var obj = new Student

{

Name = "Adi",

Id = 1

};

HttpContext.Response.Headers.Add("x-custom-header-from-action 1", "my custom value 1");

return Ok(obj);

}

How to enable CORS in ASP.NET Core

 open startup.cs page .net core project

In ConfigureServices() method:

public void ConfigureServices(IServiceCollection services)

{

 --------                 

  services.AddCors();

 --------

}

In Configure() method:

public void Configure(IApplicationBuilder app, IWebHostEnvironment env)

  {

  --------

   app.UseCors(builder =>

          builder.AllowAnyOrigin()

          .AllowAnyHeader()

          .AllowAnyMethod()

        );

  --------

  }