Get age to calculate from birthday in T-SQL and ASP.NET Core MVC

Question

I would like it to be calculated here is what I have tried:

public int AgeCalc
{
    get
    {
        DateTime now = DateTime.Today;
        int agecalc = now.Year - DoB.Year;

        if (DoB > now.AddYears(-Age)) 
             Age--;

        return Age;
    }
}

but I get this error:

'-' cannot be applied.

I have a column in my database table called Age. What I want it to do is when a date is selected in the DoB (Date of Birth) column, it calculates the age of the person.

This is my T-SQL code:

CREATE TABLE [dbo].[Students]
(
    [StudentId] INT NOT NULL IDENTITY(1,1) PRIMARY KEY,
    [FirstName] nvarchar(200) NOT NULL,
    [LastName] nvarchar(400) NOT NULL,
    [DoB] datetime NULL,
    [Age] int NOT NULL,
    [Gender] char(10) NULL CHECK (Gender = 'Male' OR Gender = 'Female' OR Gender = 'Other'),
    [ParentOrGuardian] nvarchar(400),
    [PaymentEmail] varchar(255) NOT NULL,
    [ContactNumber] char(10) NULL
)

This is my model class in C#:

namespace MusicDataApplication.Models
{
    using Microsoft.Ajax.Utilities;
    using System;
    using System.Collections.Generic;
    using System.ComponentModel.DataAnnotations;
    using System.Data.Entity.Core.Common.CommandTrees.ExpressionBuilder;

    public partial class Student
    {
        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2214:DoNotCallOverridableMethodsInConstructors")]
        public Student()
        {
            this.Lessons = new HashSet<Lesson>();
        }
    
        public int StudentId { get; set; }

        [Display(Name = "First Name")]
        public string FirstName { get; set; }

        [Display(Name = "Last Name")]
        public string LastName { get; set; }

        [Display(Name = "Birthday")]
        [DataType(DataType.Date)]
        public Nullable<System.DateTime> DoB { get; set; }

        public int Age { get; set; }
        public string Gender { get; set; }

        [Display(Name = "Parent/ Guardian")]
        public string ParentOrGuardian { get; set; }
        [Display(Name = "Payement Email")]
        [DataType(DataType.EmailAddress)]
        public string PaymentEmail { get; set; }
        [Display(Name = "Contact Number")]
        public string ContactNumber { get; set; }
    
        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2227:CollectionPropertiesShouldBeReadOnly")]
        public virtual ICollection<Lesson> Lessons { get; set; }
    }
}

https://www.wiseowl.co.uk/blog/s216/calculating_age_in_sql_server.htm But why store it in the DB rather than calculating it when you need it, bearing in mind it might be different tomorrow from what it is today? — stuartd, Oct 06 '22 at 01:40
So do you want to calculate the age only right? Or do you have any expected format? However, you can do that many ways, you can calculate it while taking input from user in `frontend`, you can either calculate in backend `C#` then can save the calculated value in database. — Md Farid Uddin Kiron, Oct 06 '22 at 02:08
Sorry I would like it to be calculated and displayed in the application — MarcusLee, Oct 06 '22 at 02:13
try this DateTime.Today.Subtract(new DateTime(1960,01,01)).TotalDays / 365.25 — Anirudha Gupta, Oct 06 '22 at 02:50
@MarcusLee Please have a try the solution and feel free to share if you encounter any issue while implementing that. — Md Farid Uddin Kiron, Oct 06 '22 at 06:20
Also see https://stackoverflow.com/questions/9/how-do-i-calculate-someones-age-based-on-a-datetime-type-birthday — Matthew Watson, Oct 06 '22 at 08:28

Md Farid Uddin Kiron · Accepted Answer · 2022-10-06T06:41:03.740

I have checked your code. However, you could achieve that in following way which is more elegant efficient.

Calculate Method:

public object CalculateAge(DateTime dateOfBirth)
        {
            //DateTime birth = new DateTime(1990, 08, 02);
            DateTime birth = dateOfBirth;
            DateTime today = DateTime.Now;
            TimeSpan span = today - birth;
            DateTime age = DateTime.MinValue + span;

            // Make adjustment due to MinValue equalling 1/1/1int years = age.Year - 1;
            int months = age.Month - 1;
            int days = age.Day - 1;

            // You even can Print out not only how many years old they are but give months and days as well
            var ageInYMD = string.Format("{0} years, {1} months, {2} days", age.Year, months, days);
            var ageInY = string.Format("{0} years", age.Year);

            return age.Year;
        }

Model:

public class CalculateStudentsAgeModel
    {
        [Key]
        public int StudentId { get; set; }
        public string FirstName { get; set; }
        public string LastName { get; set; }
        public DateTime DoB { get; set; }
        public int Age { get; set; }
       
        public string Gender { get; set; }
       
    }

HTML: Razor View:

@model MVCApps.Models.CalculateStudentsAgeModel
<div>
    <form asp-action="SubmitAge" method="post" enctype="multipart/form-data">
        <div asp-validation-summary="ModelOnly"></div><input type="hidden" asp-for="StudentId" />
        <div>
            <h4><strong>Student Details</strong> </h4>

            <table class="table table-sm table-bordered table-striped">

                <tr>
                    <th> <label asp-for="FirstName"></label></th>
                    <td> <input asp-for="FirstName" class="form-control" placeholder="Enter first name" /><span asp-validation-for="FirstName"></span></td>
                </tr>
                <tr>
                    <th> <label asp-for="LastName"></label></th>
                    <td> <input asp-for="LastName" class="form-control" placeholder="Enter last name" /><span asp-validation-for="LastName"></span></td>
                </tr>
                <tr>
                    <th> <label asp-for="Gender"></label></th>

                    <td>
                        <select asp-for="Gender" class="form-control">
                            <option value="Male">Male</option>
                            <option value="Female">Female</option>
                        </select>
                        <span asp-validation-for="Gender"></span>

                    </td>
                </tr>
                <tr>
                    <th> <label asp-for="DoB"></label></th>
                    <td> <input asp-for="DoB" id="dateOfBirth" class="form-control" placeholder="Enter date of birth" /><span asp-validation-for="DoB"></span></td>
                </tr>
                <tr>
                    <th> <label asp-for="Age"></label></th>
                    <td> <input asp-for="Age" id="Age"  class="form-control" readonly placeholder="Calculated age" /><span asp-validation-for="Age"></span></td>
                </tr>

                <tr>
                    <th>  <button type="submit" class="btn btn-primary" style="width:107px">Save Info</button></th>
                    <td> </td>
                </tr>
                <tr>
                    <th>@Html.ActionLink("Back To List", "MemberList", new { /* id=item.PrimaryKey */ }, new { @class = "btn btn-success" })</th>
                    <td> </td>
                </tr>
            </table>
        </div>
    </form>

</div>

@section scripts {
    <script src="https://ajax.aspnetcdn.com/ajax/jQuery/jquery-3.2.1.min.js"></script>
    <script>
        $(document).ready(function () {

         
            $('#dateOfBirth').change(function () {
               
                var dateOfBirth = $('#dateOfBirth').val();

                console.log(dateOfBirth);
                $.ajax({
                    url: '/Userlog/CalulateAgeFromDob',
                    type: 'GET',
                    dataType: 'json',
                    data: { dateOfBirth: dateOfBirth },
                    success: function (response) {
                        console.log(response);
                        $("#Age").val(response);
                    },
                    error: function () {
                        alert('Error!');
                    }
                });
            });

        });
    </script>
}

Controller:Load View:

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

Controller:API Calculate Age:

        [HttpGet]
        public ActionResult CalulateAgeFromDob(DateTime dateOfBirth)
        {
            var age = CalculateAge(dateOfBirth);
            return Json(age);
        }

Note: I am calling CalculateAge method while selecting the DOB and calling the API from backend.

Controller:Submit Value and Save :

        [HttpPost]
        public IActionResult SubmitAge(CalculateStudentsAgeModel studentsAgeModel)
        {
            _context.calculateStudentsAgeModels.Add(studentsAgeModel);
            _context.SaveChanges();

            return RedirectToAction("ViewCalculateAge");
        }

Output:

Get age to calculate from birthday in T-SQL and ASP.NET Core MVC

1 Answers1