How to check whether a base class object or derived object?

Question

I have a BankAccount class. FixedBankAccount and SavingsBankAccount are derived from it.
I need to throw an exception if the recieved object is not a derived object. I have the following code.

IEnumerable<DBML_Project.BankAccount> accounts = AccountRepository.GetAllAccountsForUser(userId);
foreach (DBML_Project.BankAccount acc in accounts)
{
    string typeResult = Convert.ToString(acc.GetType());
    string baseValue = Convert.ToString(typeof(DBML_Project.BankAccount));

    if (String.Equals(typeResult, baseValue))
    {
        throw new Exception("Not correct derived type");
    }
}

namespace DBML_Project
{

public  partial class BankAccount
{
    // Define the domain behaviors
    public virtual void Freeze()
    {
        // Do nothing
    }
}

public class FixedBankAccount : BankAccount
{
    public override void Freeze()
    {
        this.Status = "FrozenFA";
    }
}

public class SavingsBankAccount : BankAccount
{
    public override void Freeze()
    {
        this.Status = "FrozenSB";
    }
}

} // namespace DBML_Project

Is there any better code than this?

Answer 1

You should be using Type.IsAssignableFrom

if (acc.GetType().IsAssignableFrom(typeof(BankAccount)))
    // base class
else
    // derived