How to save custom value in ID column using Entity Framework 6

Question

I am using code first approach, I don't know how to pass custom id into ID column Whenever I try to pass id its show the following error:

Can't insert null to table Orders.ID Insert fails

public class Order 
{       
    [Key]
    public int  ID { get; set; } // I WANT THIS COLUMN SHOULD BE SAVED AS "10001,10002,10003" INSTEAD OF "1,2,3,4"
    public string CustomerID { get; set; }
    public string CustomerName { get; set; }
    public string CustomerEmail { get; set; }

    public virtual List<OrderItem> OrderItems { get; set; }
    
    public virtual List<OrderHistory> OrderHistory { get; set; }
}

public class OrderHistory 
{
   
    public int OrderID { get; set; }
    public int OrderStatus { get; set; }
    public string Note { get; set; }
}

public class OrderItem 
{        
    public int OrderID { get; set; }

    [NotMapped]
    public string ProductName { get; set; }
    public int ProductID { get; set; }
  
    public virtual Product Product { get; set; }

    /// <summary>
    /// Item Price is in Order Item because we can have a scenerio where we might charge less or greater than the Product Price.
    /// </summary>
    public decimal ItemPrice { get; set; }

    public int Quantity { get; set; }
}

EDIT-2

After adding on ID its now throwing another error as Invalid column name 'ID' Invalid column name 'ID'

 [Key]
 [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
 public int ID { get; set; }
    

Answer 1

Considering your scenario you could implement like below ways. I have work around using this command while you add migration command , before that you could add this like below

 migrationBuilder.Sql("DBCC CHECKIDENT ('Order ', RESEED, 10001)"); 

Though you could add expected sequence for non primary key column but so far I have tested it does't work for primary key column because migration always add this commands. Which enforced SQL server to take the controls of identity

.Annotation("SqlServer:ValueGenerationStrategy", SqlServerValueGenerationStrategy.IdentityColumn)

Note: So we need to add above mensioned command to override it. Which implement the custom identity as we want.

Hope it will help you to acheive your goal.