1.WEB,API -> connection string appsettings.json
--------------------------------------------------
2.DataModel - Student.cs
namespace Kolokwium.Model.DataModels;
public class Student : User
{
    public required string NrIndexu {get; set;}
}
--------------------------------------------------
3.VM - StudentVm.cs
namespace Kolokwium.ViewModel.VM;
public class StudentVm
{
    public int? Id {get; set;}
    public required string Imie {get; set;}
    public required string Nazwisko {get; set;}
    public required string NrIndexu {get; set;}
    public required string Email {get; set;}
}
****************************
VM - ModifyStudentVm.cs
namespace Kolokwium.ViewModel.VM;
public class ModifyStudentVm
{
    public int? Id {get; set;}
    public required string Imie {get; set;}
    public required string Nazwisko {get; set;}
    public required string NrIndexu {get; set;}
    public required string Email {get; set;}
}
--------------------------------------------------
4.Services -> Interfaces - IStudentService.cs
using System.Linq.Expressions;
using Kolokwium.Model.DataModels;
using Kolokwium.ViewModel.VM;

namespace Kolokwium.Services.Interfaces;
public interface IStudentService
{
    IEnumerable<StudentVm> GetStudentVms(Expression<Func<Student,bool>>? predicate = null);
    StudentVm GetStudentVm(Expression<Func<Student,bool>> predicate);
    Student Modify(ModifyStudentVm ModifyStudentVm);
    void DeleteStudent(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 StudentService : BaseService, IStudentService
{
    public StudentService(ApplicationDbContext dbContext, IMapper mapper, ILogger logger) : base(dbContext, mapper, logger)
    {
    }

    public Student Modify(ModifyStudentVm ModifyStudentVm)
    {
        try
        {
            if(ModifyStudentVm == null)
                throw new Exception("Error");
            var student = Mapper.Map<Student>(ModifyStudentVm);
            if(!ModifyStudentVm.Id.HasValue)
            {
                DbContext.Students.Add(student);
                DbContext.SaveChanges();
                return student;
            }
            else//usunąć ifa albo else
            {
                var oldStudent = DbContext.Students.Find(ModifyStudentVm.Id);
                if(oldStudent == null)
                    throw new Exception();
                oldStudent.Imie = student.Imie;
                oldStudent.Nazwisko = student.Nazwisko;
                oldStudent.Email = student.Email;
                oldStudent.NrIndexu = student.NrIndexu;
                DbContext.SaveChanges();
                return oldStudent;
            }
        }
        catch(Exception e)
        {
            Logger.LogError(e,e.Message);
            throw;
        }
    }

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

    public StudentVm GetStudentVm(Expression<Func<Student, bool>> predicate)
    {
        try
        {
            if(predicate == null)
                throw new Exception();
            var student = DbContext.Students.FirstOrDefault(predicate);
            if(student == null)
                throw new Exception();
            var studentVm = Mapper.Map<StudentVm>(student);
            return studentVm;
        }
        catch(Exception e)
        {
            Logger.LogError(e,e.Message);
            throw;
        }
    }

    public IEnumerable<StudentVm> GetStudentVms(Expression<Func<Student, bool>>? predicate = null)
    {
        try
        {
            var students = DbContext.Students.AsQueryable();
            if(predicate != null)
            {
                students.Where(predicate);
            }
            var studentsVm = Mapper.Map<IEnumerable<StudentVm>>(students);
            return studentsVm;
        }
        catch(Exception e)
        {
            Logger.LogError(e,e.Message);
            throw;
        }
    }
}
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6.Configuration -> MainProfile.cs
CreateMap<Student,StudentVm>();
CreateMap<ModifyStudentVm,Student>();
CreateMap<StudentVm,ModifyStudentVm>();
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7.----
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8.---
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9.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 StudentController : BaseController
{
    private readonly IStudentService studentService1;
    public StudentController(ILogger logger, IMapper mapper, IStringLocalizer localizer, IStudentService studentService) : base(logger, mapper, localizer)
    {
        studentService1 = studentService;
    }

    public IActionResult Index()
    {
        var studentsVm = studentService1.GetStudentVms();
        return View(studentsVm);
    }

    public IActionResult Modify(int? id = null)
    {
        if(id == null)
            return View();
        else
        {
            var student = studentService1.GetStudentVm(x => x.Id == id);
            var ModifyStudentVm = Mapper.Map<ModifyStudentVm>(student);
            return View(ModifyStudentVm);
        }
    }//usunąć else,parametr i ifa

    [HttpPost]
    public IActionResult Modify(ModifyStudentVm ModifyStudentVm)
    {
        if(ModifyStudentVm == null)
            throw new Exception();
        studentService1.Modify(ModifyStudentVm);
        return RedirectToAction(nameof(Index));
    }

    public IActionResult DeleteStudent(int id)
    {
        studentService1.DeleteStudent(id);
        return RedirectToAction(nameof(Index));
    }
}
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10.Web -> Program.cs
builder.Services.AddTransient<IStudentService,StudentService>();
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12.Shared -> Layout
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14.DAL -> DbContext
public virtual DbSet<Student> Students {get; set;} = null!;


dotnet ef migrations add migrancja1 --project Kolokwium.DAL --startup-project Kolokwium.Web
dotnet ef database update --project Kolokwium.DAL --startup-project Kolokwium.Web

dotnet aspnet-codegenerator view -p Kolokwium.Web Index List -m StudentVm -outDir Views/Student -scripts -udl
dotnet aspnet-codegenerator view -p Kolokwium.Web Modify Create -m ModifyStudentVm -outDir 
Views/Student -scripts -udl

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16.Web -> Views -> Index
Zmienić akcje
@Html.ActionLink("Edit", "Modify", new {id = item.Id}) |
@Html.ActionLink("Delete", "DeleteSportowiec", new {id = item.Id})
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17.Usunąć ID z Modify.cshtml
18.dotnet run --project Kolokwium.Web



UWAGI:
modyfikacja Student -> index.cshtml
<a asp-action="Modify">Create New</a>
nazwe pobrac z web -> controllers -> StudentController