.net core 2 webapi + postman

using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;

namespace WebApi
{
    public class Startup
    {
        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }

        public IConfiguration Configuration { get; }

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_2);
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IHostingEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }
            else
            {
                // The default HSTS value is 30 days. You may want to change this for production scenarios, see https://aka.ms/aspnetcore-hsts.
                app.UseHsts();
            }

            app.UseMvc(routes =>
            {
                routes.MapRoute("default", "{controller=Home}/{action=Index}/{id?}");
            });

            app.UseHttpsRedirection();
        }
    }
}

using Microsoft.AspNetCore.Mvc;

namespace WebApi.Controllers
{
    [Route("api/[controller]")]
    [ApiController]
    public class HomeController : ControllerBase
    {
        public IActionResult Get()
        {
            return Ok("Get Success");
        }

        [HttpPost]
        public IActionResult Post()
        {
            return Ok("Post Success");
        }

        [HttpPut]
        public IActionResult Put()
        {
            return Ok("Put Success");
        }

        [HttpDelete]
        public IActionResult Delete()
        {
            return Ok("Delete Success");
        }
    }
}

namespace WebApi.Models
{
    public class Message
    {
        public string Message1 { get; set; }
        public string Message2 { get; set; }
    }
}

using Microsoft.AspNetCore.Mvc;
using WebApi.Models;

namespace WebApi.Controllers
{
    [Route("api/[controller]")]
    [ApiController]
    public class RouteAttributeController : ControllerBase
    {
        [Route("Index")]
        public IActionResult MyIndex()
        {
            return Ok("Index Success");
        }

        [Route("Index/{id:int}/{firstName")]
        public IActionResult MyIndex(int id)
        {
            return Ok($"Index {id} Success");
        }

        [Route("About")]
        [HttpPost]
        public IActionResult MyAbout()
        {
            return Ok("About Success");
        }

        [Route("About/{id:int}")]
        [HttpPost]
        public IActionResult MyAbout(int id)
        {
            return Ok($"About {id} Success");
        }

        [Route("ContactSingle")]
        [HttpPost]
        public IActionResult MyContact([FromBody]string message)
        {
            return Ok($"Contact {message} Success");
        }

        [Route("ContactClass")]
        [HttpPost]
        public IActionResult MyContact([FromBody]Message msg)
        {
            return Ok($"Contact {msg.Message1} {msg.Message2} Success");
        }
    }
}

using System.Collections.Generic;
using System.Linq;
using Microsoft.AspNetCore.Mvc;
using WebApi.Models;

namespace WebApi.Controllers
{
    [Route("api/[controller]")]
    [ApiController]
    public class HttpVerbController : ControllerBase
    {
        private List<Message> messages = new List<Message>
        {
            new Message { Message1 = "Message11", Message2 = "Message12" },
            new Message { Message1 = "Message21", Message2 = "Message22" },
            new Message { Message1 = "Message31", Message2 = "Message32" },
            new Message { Message1 = "Message41", Message2 = "Message42" },
            new Message { Message1 = "Message51", Message2 = "Message52" }
        };

        [HttpGet("getMessage")]
        public IActionResult GetListMessages()
        {
            return Ok(this.messages);
        }

        [HttpGet("getMessage/{id}")]
        public IActionResult GetListMessages(int id)
        {
            return Ok(this.messages.Where(o => o.Message2.Contains(id.ToString())).ToList());
        }

        [HttpPost("postMessage")]
        public IActionResult PostListMessages()
        {
            return Ok(this.messages);
        }

        [HttpPost("postMessage/{id}")]
        public IActionResult PostListMessages(int id)
        {
            return Ok(this.messages.Where(o => o.Message2.Contains(id.ToString())).ToList());
        }

        [HttpPost("postMessageSingleBody")]
        public IActionResult PostListMessages([FromBody]string message)
        {
            return Ok(this.messages.Where(o => o.Message2 == message).ToList());
        }

        [HttpPost("postMessageClassBody")]
        public IActionResult PostListMessages([FromBody]Message msg)
        {
            return Ok(this.messages.Where(o => o.Message2 == msg.Message2).ToList());
        }
    }
}

using Microsoft.AspNetCore.Mvc;

namespace WebApi.Controllers
{
    [Route("api/[controller]")]
    [ApiController]
    public class ResponseTypeController : ControllerBase
    {
        [HttpGet("getResponse/{id}")]
        public IActionResult GetResponse(int id)
        {
            switch (id)
            {
                case 1:
                    return Ok("Success");
                case 2:
                    return BadRequest("BadRequest");
                default:
                    return NotFound("NotFound");
            }
        }
    }
}