1.WEB,API -> connection string appsettings.json
############################################################
2.DataModel - Client.cs
namespace Kolokwium.Model.DataModels;


public class Client{

    public int Id{get;set;}//czy moze byc nullem?
    public DateTime RegistrationDate{get;set;}
    public string FirstName{get;set;}=null!;
    public string LastName{get;set;}=null!;
    public string Email{get;set;}=null!;
    public string Phone{get;set;}=null!;
    public ICollection<Order> Orders{get;set;}=null!;


}
Order{
public Client Client{get;set;}=null!;-------one to many
}
---------------------------------------------------------------
namespace Kolokwium.Model.DataModels;


public class Order{
    public int Id{get;set;}
    public DateTime CreationDate{get;set;}
    public string ShippingAdress{get;set;}=null!;
    public string? Description{get;set;}
    public string Status{get;set;}=null!;
    public int TotalAmount{get;set;}
    public DateTime DueDate{get;set;}
    public int ClientId{get;set;}
    public Client Client{get;set;}=null!;
    public ICollection<Product> Products{get;set;}=null!;
}

#############################################################
3.VM - ClientVm.cs
using Kolokwium.Model.DataModels;

namespace Kolokwium.ViewModel.VM;
public class ClientVm
{
    public int? Id{get;set;}
    public DateTime RegistrationDate{get;set;}
    public string FirstName{get;set;}=null!;
    public string LastName{get;set;}=null!;
    public string Email{get;set;}=null!;
    public string Phone{get;set;}=null!;
    public ICollection<OrderVm> Orders{get;set;}=null!;
}

----------------------------------------------------------
VM - ModifyClientVm.cs
namespace Kolokwium.ViewModel.VM;
public class ModifyClientVm
{
    public int? Id{get;set;}
    public DateTime RegistrationDate{get;set;}
    public string FirstName{get;set;}=null!;
    public string LastName{get;set;}=null!;
    public string Email{get;set;}=null!;
    public string Phone{get;set;}=null!;
}
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4.Services ->tworzymy folder Interfaces - IStudentService.cs
using System.Linq.Expressions;
using Kolokwium.Model.DataModels;
using Kolokwium.ViewModel.VM;

namespace Kolokwium.Services.Interfaces;
public interface IClientService
{
    IEnumerable<ClientVm> GetClientVms(Expression<Func<Client,bool>>? predicate = null);
    ClientVm GetClientVm(Expression<Func<Client,bool>> predicate);
    Client Modify(ModifyClientVm ModifyClientVm);
    void DeleteClient(int id);
}
##############################################################
5.ConcreteServices -> StudentService.cs
using System.Linq.Expressions;
using System.Security.Cryptography.X509Certificates;
using AutoMapper;
using Kolokwium.DAL;
using Kolokwium.Model.DataModels;
using Kolokwium.Services.Interfaces;
using Kolokwium.ViewModel.VM;
using Microsoft.EntityFrameworkCore.Diagnostics;
using Microsoft.Extensions.Logging;

namespace Kolokwium.Services.ConcreteServices;
public class ClientService : BaseService, IClientService
{
    public ClientService(ApplicationDbContext dbContext, IMapper mapper, ILogger logger) : base(dbContext, mapper, logger)
    {
    }

    public Client Modify(ModifyClientVm ModifyClientVm)
    {
        try
        {
            if(ModifyClientVm == null)
                throw new Exception("Error");
            var Client = Mapper.Map<Client>(ModifyClientVm);
            if(!ModifyClientVm.Id.HasValue)
            {
                DbContext.Clients.Add(Client);
                DbContext.SaveChanges();
                return Client;
            }
            else
            {
                var oldClient = DbContext.Clients.Find(ModifyClientVm.Id);
                if(oldClient == null)
                    throw new Exception();
                oldClient.RegistrationDate = Client.RegistrationDate;
                oldClient.FirstName = Client.FirstName;
                oldClient.LastName = Client.LastName;
                oldClient.Email = Client.Email;
                oldClient.Phone = Client.Phone;
                DbContext.SaveChanges();
                return oldClient;
            }
        }
        catch(Exception e)
        {
            Logger.LogError(e,e.Message);
            throw;
        }
    }

    public void DeleteClient(int id)
    {
        try
        {
            var Client = DbContext.Clients.FirstOrDefault(x => x.Id == id);
            if(Client == null)
                throw new Exception();
            DbContext.Clients.Remove(Client);
            DbContext.SaveChanges();
        }
        catch(Exception e)
        {
            Logger.LogError(e,e.Message);
        }
    }

    public ClientVm GetClientVm(Expression<Func<Client, bool>> predicate)
    {
        try
        {
            if(predicate == null)
                throw new Exception();
            var Client = DbContext.Clients.FirstOrDefault(predicate);
            if(Client == null)
                throw new Exception();
            var ClientVm = Mapper.Map<ClientVm>(Client);
            return ClientVm;
        }
        catch(Exception e)
        {
            Logger.LogError(e,e.Message);
            throw;
        }
    }

    public IEnumerable<ClientVm> GetClientVms(Expression<Func<Client, bool>>? predicate = null)
    {
        try
        {
            var Clients = DbContext.Clients.AsQueryable();
            if(predicate != null)
            {
                Clients.Where(predicate);
            }
            var ClientsVm = Mapper.Map<IEnumerable<ClientVm>>(Clients);
            return ClientsVm;
        }
        catch(Exception e)
        {
            Logger.LogError(e,e.Message);
            throw;
        }
    }
}

#########################################################################################################
6.Configuration -> MainProfile.cs //ZRÓB USINGI ctrl .//*2
CreateMap<Student,StudentVm>();
CreateMap<ModifyStudentVm,Student>();
CreateMap<StudentVm,ModifyStudentVm>();
###########################################################################################
7.Web -> Controllers -> StudentController.cs
using AutoMapper;
using Kolokwium.Model.DataModels;
using Kolokwium.Services.ConcreteServices;
using Kolokwium.Services.Interfaces;
using Kolokwium.ViewModel.VM;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Localization;

namespace Kolokwium.Web.Controllers;
public class ClientController : BaseController
{
    private readonly IClientService ClientService1;
    public ClientController(ILogger logger, IMapper mapper, IStringLocalizer localizer, IClientService ClientService) : base(logger, mapper, localizer)
    {
        ClientService1 = ClientService;
    }

    public IActionResult Index()
    {
        var ClientsVm = ClientService1.GetClientVms();
        return View(ClientsVm);
    }

    public IActionResult Modify(int? id = null)
    {
        if(id == null)
            return View();
        else
        {
            var Client = ClientService1.GetClientVm(x => x.Id == id);
            var ModifyClientVm = Mapper.Map<ModifyClientVm>(Client);
            return View(ModifyClientVm);
        }
    }

    [HttpPost]
    public IActionResult Modify(ModifyClientVm ModifyClientVm)
    {
        if(ModifyClientVm == null)
            throw new Exception();
        ClientService1.Modify(ModifyClientVm);
        return RedirectToAction(nameof(Index));
    }

    public IActionResult DeleteClient(int id)
    {
        ClientService1.DeleteClient(id);
        return RedirectToAction(nameof(Index));
    }
}
#####################################################################
8.Web -> Program.cs//*2
builder.Services.AddTransient<IStudentService,StudentService>();
#####################################################################
9.dotnet aspnet-codegenerator view -p Kolokwium.Web Index List -m StudentVm -outDir Views/Student -scripts -udl
########################################################################
10.Shared -> Layout
  <li class="nav-item">
     <a class="nav-link text-dark" asp-area="" asp-controller="Sportowiec" asp-action="Index">Sportowcy</a>
  </li>
###########################################################################
11.DAL -> DbContext//*3
public virtual DbSet<Student> Students {get; set;} = null!;
##########################################################################
12.dotnet aspnet-codegenerator view -p Kolokwium.Web Modify Create -m ModifyStudentVm -outDir 
Views/Student -scripts -udl                       //Wpisuj ręcznie lepiej xddd
###########################################################################
13.Web -> Views -> Index
Wywal Details
Zmienić akcje
@Html.ActionLink("Edit", "Modify", new {id = item.Id}) |
@Html.ActionLink("Delete", "DeleteSportowiec", new {id = item.Id})

W 10 linii zmień Create na Modify xdddd
#########################################################################
14.Usunąć ID z Modify.cshtml

Dodaj na poczatku w @:  var clients=ViewBag.Clients;
potem zamien diva z ClientId

            <div class="form-group">
                <label asp-for="ClientId" class="control-label"></label>
                <select asp-for="ClientId" class="form-control">
                    @foreach(var c in clients){
                        <option value="@c.Id">@c.FirstName</option>
                    }
                </select>
            </div>

#############################################################################
Polecenia:

1.  dotnet ef migrations add migrancja1 --project Kolokwium.DAL --startup-project Kolokwium.Web
2.  dotnet ef database update --project Kolokwium.DAL --startup-project Kolokwium.Web
2*3.  dotnet aspnet-codegenerator view -p Kolokwium.Web Index List -m StudentVm -outDir Views/Student -scripts -udl
2*4.  dotnet aspnet-codegenerator view -p Kolokwium.Web Modify Create -m ModifyStudentVm -outDir Views/Student -scripts -udl
5.  dotnet run --project Kolokwium.Web