Creating Primary Key field on MVC class

I am new to MVC and C#. I just stumbled on it and found it interesting. I encountered an issue which will not allow me proceed.
Here is my code:

`using System;
  using System.Collections.Generic;
  using System.Linq;
  using System.Web;
  using System.Web.Mvc; 
 
  namespace MyHotel.Models
  {
     public class AccountTypes
     {
         public int AccountTypeID { get; set; }
         public string AccountTypeName { get; set; }
    }
  }
 

`
I created the controler and the view thereafter.

And for this, I keep got this error:

One or more validation errors were detected during model generation:

`System.Data.Edm.EdmEntityType: : EntityType 'AccountTypes' has no key defined. Define      the key for this EntityType.
 

System.Data.Edm.EdmEntitySet: EntityType: EntitySet "AccountTypes" is based on type "AccountTypes" that has no keys defined.`

I google that the answers were to add [Key] over the public int AccountTypeID { get; set; } so it could look like this:

`namespace MyHotel.Models
    {
      public class AccountTypes
      {
       [Key]
       public int AccountTypeID { get; set; }
       public string AccountTypeName { get; set; }
      }
   }
 `
 

But no result till now.
I will appreciate any help.
Note: I am using MVC 4

Peter

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