How to do Insert update,delete and list on one view

Hey Mark,

Please use this example,

Create model for student, Course and StudentCourse mapper calss and view model

public class Student
{
    public int Id { get; set; }
    public string Name { get; set; }
    public List StudentCourses { get; set; }
}


public class Course
{
    public int Id { get; set; }
    public string Title { get; set; }
    public List StudentCourses { get; set; }
}


// Student course mapper class
public class StudentCourse
{
    public int StudentId { get; set; }
    public Student Student { get; set; }
    public int CourseId { get; set; }
    public Course Course { get; set; }
}


// View Model for Student course
public class StudentCourseViewModel
{
    public Student Student { get; set; }
    public List AvailableCourses { get; set; }
    public List SelectedCourseIds { get; set; } = new List();
}

Create Controller :

// Controllers/StudentController.cs
public class StudentController : Controller
{
    private readonly ApplicationDbContext _context;

    public StudentController(ApplicationDbContext context)
    {
        _context = context;
    }

    public async Task Index()
    {
        var students = await _context.Students.Include(s => s.StudentCourses).ThenInclude(sc => sc.Course).ToListAsync();
        return View(students);
    }

    public IActionResult Create()
    {
        var viewModel = new StudentCourseViewModel
        {
            AvailableCourses = _context.Courses.ToList()
        };
        return View(viewModel);
    }

    [HttpPost]
    public async Task Create(StudentCourseViewModel viewModel)
    {
        if (ModelState.IsValid)
        {
            var student = new Student
            {
                Name = viewModel.Student.Name,
                StudentCourses = viewModel.SelectedCourseIds.Select(courseId => new StudentCourse
                {
                    CourseId = courseId
                }).ToList()
            };

            _context.Students.Add(student);
            await _context.SaveChangesAsync();
            return RedirectToAction(nameof(Index));
        }

        viewModel.AvailableCourses = _context.Courses.ToList();
        return View(viewModel);
    }

    public async Task Edit(int id)
    {
        var student = await _context.Students.Include(s => s.StudentCourses).ThenInclude(sc => sc.Course).FirstOrDefaultAsync(s => s.Id == id);
        if (student == null) return NotFound();

        var viewModel = new StudentCourseViewModel
        {
            Student = student,
            AvailableCourses = _context.Courses.ToList(),
            SelectedCourseIds = student.StudentCourses.Select(sc => sc.CourseId).ToList()
        };

        return View(viewModel);
    }

    [HttpPost]
    public async Task Edit(StudentCourseViewModel viewModel)
    {
        if (ModelState.IsValid)
        {
            var student = await _context.Students.Include(s => s.StudentCourses).FirstOrDefaultAsync(s => s.Id == viewModel.Student.Id);
            if (student == null) return NotFound();

            student.Name = viewModel.Student.Name;

            var existingCourseIds = student.StudentCourses.Select(sc => sc.CourseId).ToList();
            var newCourseIds = viewModel.SelectedCourseIds;

            var coursesToRemove = student.StudentCourses.Where(sc => !newCourseIds.Contains(sc.CourseId)).ToList();
            var coursesToAdd = newCourseIds.Where(id => !existingCourseIds.Contains(id)).Select(id => new StudentCourse
            {
                StudentId = student.Id,
                CourseId = id
            }).ToList();

            _context.StudentCourses.RemoveRange(coursesToRemove);
            _context.StudentCourses.AddRange(coursesToAdd);

            await _context.SaveChangesAsync();
            return RedirectToAction(nameof(Index));
        }

        viewModel.AvailableCourses = _context.Courses.ToList();
        return View(viewModel);
    }

    public async Task Delete(int id)
    {
        var student = await _context.Students.FindAsync(id);
        if (student == null) return NotFound();

        _context.Students.Remove(student);
        await _context.SaveChangesAsync();
        return RedirectToAction(nameof(Index));
    }
}

Create View :

@model IEnumerable

Students


    @foreach (var student in Model)
    {
        
    }
    

    

        

            
Name
            
Courses
            

        
    
    

            
@student.Name
            

                @foreach (var course in student.StudentCourses.Select(sc => sc.Course))
                {
                    @course.Title

                }
            
            

                Edit
                Delete
            
        


Add New Student

Edit View

@model StudentCourseViewModel

@(Model.Student.Id == 0 ? "Create Student" : "Edit Student")


    

        
        
        
    

    

        Courses
        
    

    

        Save
    

The issue is i am using viewmodel and let say I have two models student and courses as below 
public class student

{

public int id {get;set;}

public string name{get;set;}

}

public class coruse

{

public int id {get;set;}

public string name{get;set;}

}

My ViewModel is like below 
public class MyVM

{

public student stu{get;set;}

public course cur{get;set;}

}

my index view need List and List and my create view does not need list so if we put all of them in one view how I adjust my model like for create it shoud not be list and for lising it should be list .
Abhishek Yadav yes I have a partial view and for listing and I give model as List to it but when I render the view it says the main view in which I have parital view does not have Ieneumerable or list so the partial view should have the same model as the main view have. thats the problem any example here 

let’s assume you have a Product model

public class Product
{
    public int Id { get; set; }
    public string Name { get; set; }
    public decimal Price { get; set; }
}

Next, create a controller to handle the logic.

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

public class ProductsController : Controller
{
    private static List _products = new List
    {
        new Product { Id = 1, Name = "Product1", Price = 10.0m },
        new Product { Id = 2, Name = "Product2", Price = 20.0m }
    };

    // GET: Products
    public IActionResult Index()
    {
        return View(_products);
    }

    // POST: Products/Add
    [HttpPost]
    public IActionResult Add(Product product)
    {
        if (ModelState.IsValid)
        {
            product.Id = _products.Max(p => p.Id) + 1;
            _products.Add(product);
        }
        return RedirectToAction(nameof(Index));
    }

    // POST: Products/Update
    [HttpPost]
    public IActionResult Update(Product product)
    {
        if (ModelState.IsValid)
        {
            var existingProduct = _products.FirstOrDefault(p => p.Id == product.Id);
            if (existingProduct != null)
            {
                existingProduct.Name = product.Name;
                existingProduct.Price = product.Price;
            }
        }
        return RedirectToAction(nameof(Index));
    }

    // POST: Products/Delete
    [HttpPost]
    public IActionResult Delete(int id)
    {
        var product = _products.FirstOrDefault(p => p.Id == id);
        if (product != null)
        {
            _products.Remove(product);
        }
        return RedirectToAction(nameof(Index));
    }
}

Now, create a view to handle all actions in a single page.

Index.cshtml

@model IEnumerable
@{
    ViewData["Title"] = "Product Management";
}

Product Management


Add Product

    
    

        Name:
        
    
    

        Price:
        
    
    Add



Update Product

    
    

        Name:
        
    
    

        Price:
        
    
    Update



Delete Product

    

        Product Id:
        
    
    Delete



Product List

        @foreach (var product in Model)
        {
            
        }
    

    

        

            
ID
            
Name
            
Price
        
    
    

                
@product.Id
                
@product.Name
                
@product.Price
            

1. Model: Defines the structure of your data.

2. Controller: Handles the CRUD operations. Index returns the view, Add adds a new item, Update updates an existing item, and Delete removes an item.

3. Views:

   • Index.cshtml: Contains the form for adding items and displays the list of items. It uses AJAX to interact with the server without refreshing the page.
   • _ItemsList.cshtml: A partial view that lists items and can be dynamically updated.

4. JavaScript: Uses jQuery to send AJAX requests to the server to perform CRUD operations and update the view accordingly.

This approach provides a single-page interface for managing records, improving the user experience by avoiding full page reloads.