Dropdown list group in C#

In my ASP.NET MVC web application, I have a table that I planned to design which contains the main account and the subaccounts in the same table.

First I will show how I expected to get the final output on my dropdown list.

Income

Bank Account
Credit Card

Expenses

Office Expenses
Other Expenses

So as you can see upper section, Bold one's are the main accounts and the within that accounts are the sub accounts.

[Key]
public int ID { get; set; }

[Required]
public string AccountName { get; set; }

public int? MainAccountID{ get; set; }

I hope to save the data in the table like this:

I want to know, If I saved the data as I show, How to get the data and bind it to the drop-down as I show in the first section, grouping the sub-accounts under main accounts?

This can be done using separate tables, but I thought If I can save it under one table as I expected, it would be easy and fast to get the data from the model and pass it to the view. That's why I want to know about this.

Hi so TBH I wouldn't do your approach and would advocate splitting up the 2 Models into 2 different tables. You could if you want to take the apprach of have both tables being the same and using the same structure either by just having the same attributes or inheriting from the primary.

I'll show you both.

Inheriting

public class BaseClass {
   
  [Key]
   public int ID { get; set; }

   [Required]
   public string AccountName { get; set; }
} 

public class Income : BaseClass  {}

public class Outcome: BaseClass  {}

Non Inheriting

public class Income {
       [Key]
       public int ID { get; set; }
    
       [Required]
       public string AccountName { get; set; }
}
    
    public class Outcome {
      [Key]
       public int ID { get; set; }
    
       [Required]
       public string AccountName { get; set; }

   }

Personnally I wouldn't do Inheriting as the tables are really simple.

To make a select list you can use

new SelectList(_db.Incomes.OrderBy(x => x.AccountName), "ID", "AccountName");

I hope that helps with your problem and sorts you out.

If you did want to have all the rows together and do something a tad crazy (IMHO) then you could do this.

public class Account {
   
   public int ID {get;set;} 

     [Required]
           public string AccountName { get; set; }
  
    public int? MainAccountID{ get; set; }

    [ForeignKey("MainAccountID")]
    public virtual MainAccount{ get; set; }

}

Then use

var d = _db.Accounts.Where(x => x.MainAccountID != null).Include(x => x.MainAccount).OrderBy(x => x.MainAccount.AccountName).ThenBy(x => x.AccountName);

 return new SelectList(d, "MainAccountID", "AccountName ", "MainAccount.AccountName ", null, null);

Which would give a select group by the Incoming/Expenses rows.