1. Student.cs 

namespace APIWebApplication.Models
{
    public class Student
    {
        public int StuId { get; set; }
        public string StuName { get; set; }
    }
}


2. ToDoController:

        using APIWebApplication.ModelBinder;
        using APIWebApplication.Models;
        using Microsoft.AspNetCore.Mvc;

        // For more information on enabling Web API for empty projects, visit https://go.microsoft.com/fwlink/?LinkID=397860

        namespace APIWebApplication.Controllers
        {
            [Route("api/[controller]")]
            [ApiController]
            public class ToDoController : ControllerBase
            { 
                // POST api/<TodoController>
                [HttpPost("AddStudent")]
                public IActionResult Post([ModelBinder(BinderType = typeof(CustomModelBinder))] Student student)
                {
                    return Ok(student);
                } 
            }
        }

3.Custom Model Binder:

        using APIWebApplication.Models;
        using Microsoft.AspNetCore.Mvc.ModelBinding;
        using Newtonsoft.Json;

        namespace APIWebApplication.ModelBinder
        {
            public class CustomModelBinderProvider : IModelBinderProvider
            {
                public IModelBinder GetBinder(ModelBinderProviderContext context)
                {
                    if (context.Metadata.ModelType == typeof(Student))
                        return new CustomModelBinder(); 
                    return null;
                }
            }
            public class CustomModelBinder : IModelBinder
            {
                public Task BindModelAsync(ModelBindingContext bindingContext)
                {
                    if (bindingContext == null)
                        throw new ArgumentNullException(nameof(bindingContext));
                    //if the content type is "application/x-www-form-urlencoded", get the value from the Request Form
                    if (bindingContext.HttpContext.Request.ContentType== "application/x-www-form-urlencoded")
                    {
                        var student = new Student();
                        if(bindingContext.HttpContext.Request.Form.ContainsKey("StuId"))
                            student.StuId = Convert.ToInt32(bindingContext.HttpContext.Request.Form["StuId"].ToString());
                        if (bindingContext.HttpContext.Request.Form.ContainsKey("StuName"))
                            student.StuName = bindingContext.HttpContext.Request.Form["StuName"].ToString();
                        bindingContext.Result = ModelBindingResult.Success(student);
                    }
                    else if(bindingContext.HttpContext.Request.ContentType== "application/json")
                    {  //If the content type is "application/json", get the value from the request body.
                        string valueFromBody = string.Empty;
                        using (var sr = new StreamReader(bindingContext.HttpContext.Request.Body))
                        {
                            valueFromBody = sr.ReadToEnd();
                            if (string.IsNullOrEmpty(valueFromBody))
                            {
                                return Task.CompletedTask;
                            }
                            var student = JsonConvert.DeserializeObject<Student>(valueFromBody);
                            if (student != null)
                            {
                                bindingContext.Result = ModelBindingResult.Success(student);
                            }
                        }
                    } 
                    return Task.CompletedTask;
                }
            }
        }

4. Program.cs 

        using APIWebApplication.ModelBinder;
        using Microsoft.AspNetCore.Server.Kestrel.Core;

        var builder = WebApplication.CreateBuilder(args);

        // Add services to the container.

        builder.Services.AddControllers();

        builder.Services.AddControllers(o=> o.ModelBinderProviders.Insert(0, new CustomModelBinderProvider()));

        // Learn more about configuring Swagger/OpenAPI at https://aka.ms/aspnetcore/swashbuckle
        builder.Services.AddEndpointsApiExplorer();
        builder.Services.AddSwaggerGen();


        // If using Kestrel:
        builder.Services.Configure<KestrelServerOptions>(options =>
        {
            options.AllowSynchronousIO = true;
        });

        // If using IIS:
        builder.Services.Configure<IISServerOptions>(options =>
        {
            options.AllowSynchronousIO = true;
        });

        var app = builder.Build();

        // Configure the HTTP request pipeline.
        if (app.Environment.IsDevelopment())
        {
            app.UseSwagger();
            app.UseSwaggerUI();
        }

        app.UseHttpsRedirection();

        app.UseAuthorization();

        app.MapControllers();

        app.Run();