Introduction

In this post, How to implement Basic CRUD Functionality with the Entity Framework and ASP.NET MVC4 application.
I have split the entire application split into following 3 parts for making things more simple and understandable specially for beginners.

• Part 1 : Perform read functionality of CRUD Operation.
• Part 2 : Perform create and update functionality of CRUD Operation.
• Part 3 : Perform delete functionality of CRUD Operation.

Steps :

Step-1: Write function for fetch countries from database.

Here I have written the below function "GetCountry" into "Contacts" Controller.

            private List<Country> GetCountry()
            {
                using (MyDatabaseEntities dc = new MyDatabaseEntities())
                {
                    return dc.Countries.OrderBy(a => a.CountryName).ToList();
                }
            }
        

Step-2: Write function for fetch states from database.

Here I have written the below function "GetState" into "Contacts" Controller.

            private List<State> GetState(int countryID)
            {
                using (MyDatabaseEntities dc = new MyDatabaseEntities())
                {
                    return dc.States.Where(a => a.CountryID.Equals(countryID)).OrderBy(a => a.StateName).ToList();
                }
            }
        

Step-3: Write function for return state list of selected country in json format, which we will use for cascade dropdown.

Here I have written the below function "GetStateList" into "Contacts" Controller.

             public JsonResult GetStateList(int countryID)
            {
                using (MyDatabaseEntities dc = new MyDatabaseEntities())
                {
                
                    return new JsonResult { Data = GetState(countryID), JsonRequestBehavior = JsonRequestBehavior.AllowGet };
                }
            }
        

Step-4: Write function for fetch contact data from database.

Here I have written the below function "GetContact" into "Contacts" Controller.

            public Contact GetContact(int contactID)
            {
                Contact contact = null;
                using (MyDatabaseEntities dc = new MyDatabaseEntities())
                {
                    var v = (from a in dc.Contacts
                             join b in dc.Countries on a.CountryID equals b.CountryID
                             join c in dc.States on a.StateID equals c.StateID
                             where a.ContactID.Equals(contactID)
                             select new
                             {
                                 a,
                                 b.CountryName,
                                 c.StateName
                             }).FirstOrDefault();
                    if (v != null)
                    {
                        contact = v.a;
                        contact.CountryName = v.CountryName;
                        contact.StateName = v.StateName;
                    }
                    return contact;
                }
            }
        

Step-5: Add new action into your controller for get view for Save (Add and Edit) contact.

Here I have used "Save" Action. Please write this following code

            public ActionResult Save(int id = 0)
            {
                List<Country> country = GetCountry();
                List<State> states = new List<State>();
                if (id > 0)
                {
                    //Update
                    var c = GetContact(id);
                    if (c != null)
                    {
                        ViewBag.Countries = new SelectList(country, "CountryID", "CountryName", c.CountryID);
                        ViewBag.States = new SelectList(GetState(c.CountryID), "StateID", "StateName", c.StateID);
                    }
                    else
                    {
                        return HttpNotFound();
                    }
                    return View(c);
                }
                else
                {
                    //Create 
                    ViewBag.Countries = new SelectList(country, "CountryID", "CountryName");
                    ViewBag.States = new SelectList(states, "StateID", "StateName");
                    return View();
                }
            }
        

Step-6: Add view for the Action & design.

Right Click on Action Method (here right click on the action) > Add View... > Enter View Name > Select View Engine (Razor) > Check "Create a strong-typed view" > Select your model class > Add.
[N:B:Please Rebuild solution before add view.]

Step-7: Add following jquery code in the view for cascade dropdown (country > state).

Please write this following code

        <script>
        $(document).ready(function () {
            $('#CountryID').change(function () {
                var countryID = $(this).val();
                var $state = $('#StateID');
                $state.empty();
                $state.append($('<option></option>').val('').html('Please Wait...'));

                if (countryID =="") {
                    $state.empty();
                    $state.append($('<option></option>').val('').html('Select State'));
                    return;
                }

                $.ajax({
                    url: '/Contacts/GetStateList',
                    type: 'GET',
                    data: { 'countryID': countryID },
                    dataType: 'json',
                    success: function (d) {
                        $state.empty();
                        $state.append($('<option></option>').val('').html('Select State'));
                        $.each(d, function (i, val) {
                            $state.append($('<option></option>').val(val.StateID).html(val.StateName));
                        });
                    },
                    error: function () {
                        alert('Error');
                    }
                });
            });
        });
    </script>
        

Step-8: Add an another action for POST method for Save contact to the database.

Please write this following code

        [HttpPost]
        [ValidateAntiForgeryToken]
        public ActionResult Save(Contact c)
        {
            string message = "";
            bool status = false;

            //Save 
            if (ModelState.IsValid)
            {
                using (MyDatabaseEntities dc = new MyDatabaseEntities())
                {
                    if (c.ContactID > 0)
                    {
                        //Update
                        var v = dc.Contacts.Where(a => a.ContactID.Equals(c.ContactID)).FirstOrDefault();
                        if (v != null)
                        {
                            v.ContactPerson = c.ContactPerson;
                            v.ContactNo = c.ContactNo;
                            v.CountryID = c.CountryID;
                            v.StateID = c.StateID;
                        }
                        else
                        {
                            return HttpNotFound();
                        }
                    }
                    else
                    {
                        //Add new 
                        dc.Contacts.Add(c);
                    }
                    dc.SaveChanges();
                    status = true;
                    return RedirectToAction("Index");
                }
            }
            else
            {
                message = "Error! Please try again.";
                ViewBag.Countries = new SelectList(GetCountry(), "CountryID", "CountryName", c.CountryID);
                ViewBag.States = new SelectList(GetState(c.CountryID), "StateID", "StateName", c.StateID);
            }
            ViewBag.Message = message;
            ViewBag.Status = status;
            return View(c);
        }
        

Step-9: Run Application.