Implement Insert, Update and Delete Functionality in the WebGrid: Part 1

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Data.Entity;
using System.ComponentModel.DataAnnotations;
using System.Web.Mvc;
using System.Linq.Expressions;

namespace MvcApplication30.Models
{
    public class Class1
    {
        public int Student_ID { get; set; }
        public string Student_Name { get; set; }
        public string Student_Branch { get; set; }
        public string Student_City { get; set; }
        public string Student_State { get; set; }
    }

    public static class SortExtension
    {
        public static IOrderedEnumerable<TSource> OrderByWithDirection<TSource, TKey>(
            this IEnumerable<TSource> source,
            Func<TSource, TKey> keySelector,
            bool descending)
        {
            return descending ? source.OrderByDescending(keySelector)
                              : source.OrderBy(keySelector);
        }

        public static IOrderedQueryable<TSource> OrderByWithDirection<TSource, TKey>(
            this IQueryable<TSource> source,
            Expression<Func<TSource, TKey>> keySelector,
            bool descending)
        {
            return descending ? source.OrderByDescending(keySelector)
                              : source.OrderBy(keySelector);
        }
    }

    public class ModelServices : IDisposable
    {
        private readonly StudentEntities1 entities = new StudentEntities1();

        public bool SaveStudent(string name, string branch, string city, string state)
        {
            try
            {
                IT_Student stdnt = new IT_Student
                {
                    Student_Name = name,
                    Student_Branch = branch,
                    Student_City = city,
                    Student_State = state
                };
                entities.IT_Student.Add(stdnt);
                entities.SaveChanges();
                return true;
            }
            catch
            {
                return false;
            }
        }

        public bool UpdateStudent(int id, string name, string branch, string city, string state)
        {
            try
            {
                var stdnt = (from tbl in entities.IT_Student
                             where tbl.Student_Id == id
                             select tbl).FirstOrDefault();

                stdnt.Student_Name = name;
                stdnt.Student_Branch = branch;
                stdnt.Student_City = city;
                stdnt.Student_State = state;
                entities.SaveChanges();
                return true;
            }
            catch
            {
                return false;
            }
        }

        public bool DeleteStudent(int id)
        {
            try
            {
                var stdnt = (from tbl in entities.IT_Student
                             where tbl.Student_Id == id
                             select tbl).FirstOrDefault();

                entities.IT_Student.Remove(stdnt);
                entities.SaveChanges();
                return true;
            }
            catch
            {
                return false;
            }
        }

        // For Custom Paging
        public IEnumerable<IT_Student> GetStudentPage(int pageNumber, int pageSize, string sort, bool Dir)
        {
            if (pageNumber < 1) pageNumber = 1;

            if (sort == "name")
                return entities.IT_Student.OrderByWithDirection(x => x.Student_Name, Dir)
                                          .Skip((pageNumber - 1) * pageSize)
                                          .Take(pageSize)
                                          .ToList();
            else if (sort == "state")
                return entities.IT_Student.OrderByWithDirection(x => x.Student_State, Dir)
                                          .Skip((pageNumber - 1) * pageSize)
                                          .Take(pageSize)
                                          .ToList();
            else if (sort == "city")
                return entities.IT_Student.OrderByWithDirection(x => x.Student_City, Dir)
                                          .Skip((pageNumber - 1) * pageSize)
                                          .Take(pageSize)
                                          .ToList();
            else
                return entities.IT_Student.OrderByWithDirection(x => x.Student_Id, Dir)
                                          .Skip((pageNumber - 1) * pageSize)
                                          .Take(pageSize)
                                          .ToList();
        }

        public int CountStudent()
        {
            return entities.IT_Student.Count();
        }

        public void Dispose()
        {
            entities.Dispose();
        }
    }

    public class PagedStudentModel
    {
        public int TotalRows { get; set; }
        public IEnumerable<IT_Student> It_Student { get; set; }
        public int PageSize { get; set; }
    }
}

First of all, I declared some variables in this class that are similar to the column name of my table.