C#•2mo ago

FirstOrDefault and other methods are not working in LINQ

C#

using System.Diagnostics;
using Microsoft.AspNetCore.Mvc;
using practical.Models;
using System.Linq;
using System.Reflection;
using System.Runtime.Serialization;

namespace practical.Controllers;

public class CustomerController : Controller
{
    private readonly ApplicationDbContext _context;
    public CustomerController(ApplicationDbContext context)
    {
        _context = context;
    }



    public IActionResult Index()
    {
        return View();
    }

    public IActionResult CustomerRegister()
    {

        return View();
    }
    [HttpPost]
    public IActionResult CustomerRegister(customer customer)
    {
        _context.Add(customer);
        _context.SaveChanges();
        return RedirectToAction("CustomerLogin");
    }
    public IActionResult CustomerLogin()
    {
        return View();

    }
    [HttpPost]
    public IActionResult customerLogin(string Customer_email, string Customer_password)
    {
        var row = ;
        return RedirectToAction("Index");
    }

}

C#

using System.Diagnostics;
using Microsoft.AspNetCore.Mvc;
using practical.Models;
using System.Linq;
using System.Reflection;
using System.Runtime.Serialization;

namespace practical.Controllers;

public class CustomerController : Controller
{
    private readonly ApplicationDbContext _context;
    public CustomerController(ApplicationDbContext context)
    {
        _context = context;
    }



    public IActionResult Index()
    {
        return View();
    }

    public IActionResult CustomerRegister()
    {

        return View();
    }
    [HttpPost]
    public IActionResult CustomerRegister(customer customer)
    {
        _context.Add(customer);
        _context.SaveChanges();
        return RedirectToAction("CustomerLogin");
    }
    public IActionResult CustomerLogin()
    {
        return View();

    }
    [HttpPost]
    public IActionResult customerLogin(string Customer_email, string Customer_password)
    {
        var row = ;
        return RedirectToAction("Index");
    }

}

41 Replies

Technical DeveloperOP•2mo ago

So I am making login signup my signup page is working perfectly but how can write logic of Login page Without Linq methods if they are not working or how to use them why method like FirstOrDefault or Where() are not working in my code

Angius•2mo ago

Define "not working"

Technical DeveloperOP•2mo ago

! see this is a class task and I am writing code by seeing my old project

C#
        [HttpPost]
        public IActionResult customerLogin(string Customer_email, string Customer_password)
        {
            {
                var row = _context.tbl_Customer.FirstOrDefault(a => a.Customer_email == Customer_email);
                if (row != null && row.Customer_password == Customer_password)
                {
                    HttpContext.Session.SetString("customer_session", row.Customer_id.ToString());
                    return RedirectToAction("index");
                }
                else
                {
                    ViewBag.message = "Incorrect Username or Password";
                    return View();
                }
               
            }

        }

C#
        [HttpPost]
        public IActionResult customerLogin(string Customer_email, string Customer_password)
        {
            {
                var row = _context.tbl_Customer.FirstOrDefault(a => a.Customer_email == Customer_email);
                if (row != null && row.Customer_password == Customer_password)
                {
                    HttpContext.Session.SetString("customer_session", row.Customer_id.ToString());
                    return RedirectToAction("index");
                }
                else
                {
                    ViewBag.message = "Incorrect Username or Password";
                    return View();
                }
               
            }

        }

see I want something like that to get login functionality but it is not working

canton7•2mo ago

What exactly is it doing, which makes you think that it isn't working?

Technical DeveloperOP•2mo ago

it highlight its with a red line and also not show me this in intelllisense

canton7•2mo ago

Right, and what is the error message it shows in the "Error List" pane?

Technical DeveloperOP•2mo ago

canton7•2mo ago

("Not working" there could have meant that the code ran but always returned "Incorrect Username or Password" -- that's what I assumed you meant. You need to be precise when talking to other people) Can you paste the definition of ApplicationDbContext? _context.tbl_Customer should not be an instance of ApplicationDbContext

Angius•2mo ago

_context should be the ApplicationDbContext here, and tbl_Customer (as bad of a name as it is) should be a DbSet<Customer>

Technical DeveloperOP•2mo ago

Sorry I don't have a strong vocabulary like you in english

C#

  DbSet<customer> customers { get; set; }

C#

  DbSet<customer> customers { get; set; }

see i have declare it like this but it is also not getting in controller part

canton7•2mo ago

Paste the whole class, please. I want to see what tbl_Customer is

Technical DeveloperOP•2mo ago

forget tbl_Customer i was just trying to copy my old project which was similar to this in that project i named tbl_Customer in my new project it is names as customer.cs

C#

using System.ComponentModel.DataAnnotations;

namespace practical.Models
{
    public class customer
    {
        [Key]
        public int Id { get; set; }
        public string name { get; set; }
        public string email { get; set; }
        public string password { get; set; }
    }
}

C#

using System.ComponentModel.DataAnnotations;

namespace practical.Models
{
    public class customer
    {
        [Key]
        public int Id { get; set; }
        public string name { get; set; }
        public string email { get; set; }
        public string password { get; set; }
    }
}

and here is my ApplicationDbContext.cs

C#
using Microsoft.EntityFrameworkCore;

namespace practical.Models
{
    public class ApplicationDbContext:DbContext
    {
        public ApplicationDbContext(DbContextOptions<ApplicationDbContext> options )  : base (options)  
        {
            
        }
        DbSet<customer> customers { get; set; }


    }
}

C#
using Microsoft.EntityFrameworkCore;

namespace practical.Models
{
    public class ApplicationDbContext:DbContext
    {
        public ApplicationDbContext(DbContextOptions<ApplicationDbContext> options )  : base (options)  
        {
            
        }
        DbSet<customer> customers { get; set; }


    }
}

@canton7

canton7•2mo ago

I'm confused as to why the compiler didn't throw an error saying that _context.tbl_Customer doesn't exist, then You need _context.customers.FirstOrDefault(x => x.email == ...) of course

Technical DeveloperOP•2mo ago

don't mix tbl_Customer

canton7•2mo ago

What do you mean?

Technical DeveloperOP•2mo ago

because I am telling you 2nd time that I want it to create like that this tbl_Customer is my old project having this model classs this is the part of new one

canton7•2mo ago

I don't understand. Your ApplicationDbContext has DbSet<customer> customers { get; set; } . You pasted that code above. That means you need to use _context.customers

Technical DeveloperOP•2mo ago

yes i want to _context.customers table _context.customer.FirstOrDefault(c => c.id = id);

canton7•2mo ago

Yes. Do that.

Technical DeveloperOP•2mo ago

yes but the thing is when i write this line it gives me this error

canton7•2mo ago

What error?

Technical DeveloperOP•2mo ago

see attachment

canton7•2mo ago

Which attachment? Last time, you showed code which used _context.tbl_Customer, which is wrong

Technical DeveloperOP•2mo ago

see

canton7•2mo ago

Show the code above that error

Technical DeveloperOP•2mo ago

can you come on vc so i can share my screeen and

canton7•2mo ago

No, I'm at work

Technical DeveloperOP•2mo ago

betterunderstand ok!

Technical DeveloperOP•2mo ago

public IActionResult customerLogin(string Customer_email, string Customer_password)
{
    var row = _context.customers.FirstOrDefault();
    return RedirectToAction("Login");
}

public IActionResult customerLogin(string Customer_email, string Customer_password)
{
    var row = _context.customers.FirstOrDefault();
    return RedirectToAction("Login");
}

Technical DeveloperOP•2mo ago

see

canton7•2mo ago

That's a completely different error to this one: https://discord.com/channels/143867839282020352/1354050482196189184/1354059345826021398

MODiX•2mo ago

Technical Developer

Quoted by

<@660066004059029524> from #FirstOrDefault and other methods are not working in LINQ (click here)

React with ❌ to remove this embed.

canton7•2mo ago

You need public DbSet<customer> customers { get; set; }

Technical DeveloperOP•2mo ago

it is now giving me this error

C#
using Microsoft.EntityFrameworkCore;

namespace practical.Models
{
    public class ApplicationDbContext:DbContext
    {
        public ApplicationDbContext(DbContextOptions<ApplicationDbContext> options )  : base (options)  
        {
            
        }
        DbSet<customer> customers { get; set; }


    }
}

C#
using Microsoft.EntityFrameworkCore;

namespace practical.Models
{
    public class ApplicationDbContext:DbContext
    {
        public ApplicationDbContext(DbContextOptions<ApplicationDbContext> options )  : base (options)  
        {
            
        }
        DbSet<customer> customers { get; set; }


    }
}

see

canton7•2mo ago

You need public DbSet<customer> customers { get; set; }

Technical DeveloperOP•2mo ago

i have already written here `DbSet<customer> customers {get ; set}

canton7•2mo ago

You need public DbSet<customer> customers { get; set; }

Technical DeveloperOP•2mo ago

this property is already mentioned if you see my dbContext clas

canton7•2mo ago

Please read what I wrote very carefully public DbSet<customer> customers { get; set; }

Technical DeveloperOP•2mo ago

ok when i clean the solution and rebuild after adding public it now finally works thanks

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FirstOrDefault and other methods are not working in LINQ

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