Ndtyjky

I am using MVC database first approach and created one .edmx file.

Now my all the tables are available in this model.tt file.
I have also defined some dataannotation on those fields of table.

But What I have noticed that when ever I tried to update this model then value of dataanotation will be lapse.

Any thoughts please.

Yes it's kinda funny how much you read about annotations but you can't actually use them because they get overwritten.

This is what I found to help me

http://www.ozkary.com/2015/01/add-data-annotations-to-entity.html

also this

https://docs.microsoft.com/en-us/previous-versions/aspnet/ee256141(v=vs.98)

I don't pretend to understand it but here's a join the dots guide.

An example generated EF class looks like this:

public partial class Employee

{

    public int Emp_ID { get; set; }

    public string Emp_Name { get; set; }

    public Nullable<System.DateTime> Commencement_Date { get; set; }

}

Definitely do not edit this.

Instead you create a seperate class file (I called mine metadata.cs and put it in the Models folder) with this in it:

using System;

using System.ComponentModel.DataAnnotations;

using System.ComponentModel;



namespace MyProject.Models

{

    [MetadataType(typeof(EmployeeMD))]  // new name for your metadata class

    public partial class Employee    // same name as your EF generated class

    {

    // Nothing in here

    }



    internal sealed class EmployeeMD // your metadata class

    {

    [Required]

    [StringLength(50, MinimumLength = 2, ErrorMessage = "Name required")]

    public string Emp_Name { get; set; }





    [DataType(DataType.Date)]

    [DisplayFormat(DataFormatString = "{0:yyyy-MM-dd}", ApplyFormatInEditMode = true)]

    public Nullable<System.DateTime> Commencement_Date { get; set; }

    }

}