Exclude property of model in insert Entity Framework - asp.net-mvc

Question

I get an error when inserting data into my database. My database columns are:
username, password
and I added confirmpassword to the model to extend it.
How do I get rid of the confirmpassword to insert the username and password while using the model with confirmpassword property?
My code:
BootstrapTrainingEntities db = new BootstrapTrainingEntities();
var u = new User();
u.username = user.username;
u.password = user.password;
// how to I remove or ignore the confirmPassword property when saving?
db.Users.Add(u);
db.SaveChanges();
Model
[MetadataType(typeof(metadataUser))]
public partial class User
{
public string confirmPassword { get; set; }
}
public class metadataUser
{
[Required(ErrorMessage = "Username is required", AllowEmptyStrings = false)]
[Display(Name ="Username")]
public string username { get; set; }
[Required(ErrorMessage ="Password is required", AllowEmptyStrings = false)]
[Display(Name = "Password")]
[DataType(DataType.Password)]
public string password { get; set; }
[Required(ErrorMessage ="Confirmation Password is required", AllowEmptyStrings = false)]
[Display(Name ="Confiramation Password")]
[DataType(DataType.Password)]
[Compare("password",ErrorMessage = "Password does not match")]
public string confirmPassword { get; set; }
}

Answer 1

This SO has three different solutions that may help you:
How not persist property EF4 code first?
Summary:
First try the DataAnnotations approach:
Make sure you include the required library. Then apply the [Not Mapped] annotation to your field in the model.
using System.ComponentModel.DataAnnotations;
[NotMapped]
public string confirmPassword { get; set; }
If this doesn't do it, try to modify your OnModelBuilding method in your dbContext. There are two options in this block. The first is to use the Ignore method.
public class MyContext : DbContext
{
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<MetaDataUser>().Ignore(p => p.confirmPassword);
}
}
The second is to manually remap the model building and exclude your field.
Additional SO answers that may be useful:
Entity Framework Code First - How to ignore a column when saving
Exclude a field/property from the database with Entity Framework 4 & Code-First
MS Doc on how to manually map properties to db fields:
https://learn.microsoft.com/en-us/ef/core/modeling/relational/columns
Clean example of answer provided:
http://www.dotnetodyssey.com/2015/03/31/ignore-class-property-to-table-column-in-entity-framework-code-first/

Answer 2

I think what you need to do is add a viewmodel for the page.First of all you will have model that is generated from entity framework which might look as below.
public class User
{
public int id{get;set;}
public string username {get;set;}
public string password {get;set;}
}
So now create a viewModel for your View .This might look as below.
public class UserViewModel
{
public int id{get;set;}
[Required(ErrorMessage = "Username is required", AllowEmptyStrings = false)]
[Display(Name ="Username")]
public string username { get; set; }
[Required(ErrorMessage ="Password is required", AllowEmptyStrings = false)]
[Display(Name = "Password")]
[DataType(DataType.Password)]
public string password { get; set; }
[Required(ErrorMessage ="Confirmation Password is required", AllowEmptyStrings = false)]
[Display(Name ="Confiramation Password")]
[DataType(DataType.Password)]
[Compare("password",ErrorMessage = "Password does not match")]
public string confirmPassword { get; set; }
}
and now in your controller action method. you can do as below.
[HttpPost]
public ActionResult AddUser(UserViewModel model)
{
User user=new User();
user.username=model.username;
user.password=model.password;
db.User.Add(user);
}
Hope it helps !