可访问性不一致: 参数类型“XX”比方法“XX”的可访问性低的问题

namespace Csharp接口
{
    public interface IBankAccount
    {
        void PayIn(decimal amount);
        bool Withdraw(decimal amount);
        decimal Balance
        { get; }
    }

    interface ITransferBankAccount : IBankAccount
    {
        bool TransferTo(IBankAccount destination, decimal amount);
    }
}

以上是接口代码，下面是在类中实现接口的代码：

public class CurrentAccount:ITransferBankAccount
    {
        private decimal balance;
        public void PayIn(decimal amount)
        {
            balance += amount;
        }

        public bool Withdraw(decimal amount)
        {
            if (balance >= amount)
            {
                balance -= amount;
                return true;
            }
            Console.WriteLine("余额不足。");
            return false;
        }

        public decimal Balance
        {
            get
            {
                return balance;
            }
        }

        public override string ToString()
        {
            return string.Format("venus账户余额：Balance = {0,6:C}", balance);
        }

        public bool TransferTo(IBankAccount destination, decimal amount)
        {
            bool result;
            result = Withdraw(amount);
            if (result)
            {
                destination.PayIn(amount);
            }
            return result;
        }
    }

 

　其中

public bool TransferTo(IBankAccount destination, decimal amount)
方法提示编译错误会提示：可访问性不一致: 参数类型“XX”比方法“XX”的可访问性低的问题
只需要在IBankAccount接口前面加个public修饰符即可。之前未加修饰符，一直提示错误。