Question

自己学习C＃（不是作业）。程序调用所有3个重载方法 - 应该只根据用户的输入类型（int，double或string）调用一个方法。我该怎么做呢？我是否在方法中使用if语句？请基本/简单的答案。谢谢!!

static void Main(string[] args)
    {
        int entryInt;
        double entryDouble;
        string entryString;
        string userEntry;

        const double MIN = 10.00;

        Console.WriteLine("\t** WELCOME TO THE AUCTION! **\n");
        Console.Write("Please enter a bid for the item:  ");
        userEntry = Console.ReadLine();

        int.TryParse(userEntry, out entryInt);
        double.TryParse(userEntry, out entryDouble);
        entryString = userEntry.ToLower();

        BidMethod(entryInt, MIN);
        BidMethod(entryDouble, MIN);
        BidMethod(entryString, MIN);

        Console.ReadLine();
    }

    private static void BidMethod(int bid, double MIN)
    {  // OVERLOADED - ACCEPTS BID AS AN INT
        Console.WriteLine("Bid is an int.");
        Console.WriteLine("Your bid is: {0:C}", bid);
        if (bid >= MIN)
            Console.WriteLine("Your bid is over the minimum {0} bid amount.", MIN);
        else
            Console.WriteLine("Your bid is not over the minimum {0} bid amount.", MIN);
    }

    private static void BidMethod(double bid, double MIN)
    {  // OVERLOADED - ACCEPTS BID AS A DOUBLE

        Console.WriteLine("Bid is a double.");
        Console.WriteLine("Your bid is: {0:C}", bid);
        if (bid >= MIN)
            Console.WriteLine("Your bid is over the minimum {0} bid amount.", MIN);
        else
            Console.WriteLine("Your bid is not over the minimum {0} bid amount.", MIN);
    }

    private static void BidMethod(string bid, double MIN)
    {  // OVERLOADED - ACCEPTS BID AS A STRING

        string amount;
        int amountInt;

        if (bid.StartsWith("$")) 
            amount = (bid as string).Trim('$');  // Remove the $
        if (bid.EndsWith("dollar"))
            amount = bid.TrimEnd(' ', 'd', 'o', 'l', 'l', 'a', 'r', 's');
        else
            amount = bid;

        Int32.TryParse(amount, out amountInt);  // Convert to Int
        Console.WriteLine("Bid is a string.");

        Console.WriteLine("Your bid is: {0:C}", bid);
        if (amountInt >= MIN)
            Console.WriteLine("Your bid is over the minimum {0} bid amount.", MIN);
        else
            Console.WriteLine("Your bid is not over the minimum {0} bid amount.", MIN);
    }
}

}

Answer 1

这里的设计不是很好，但无论如何。请注意，TryParse方法返回布尔值，指示它们是成功还是未能解析字符串。您可以使用它来决定要调用的方法：

if (int.TryParse(userEntry, out entryInt))
{
    BidMethod(entryInt, MIN);
}
else if (double.TryParse(userEntry, out entryDouble))
{
    BidMethod(entryDouble, MIN);
}
else
{        
    entryString = userEntry.ToLower();
    BidMethod(entryString, MIN);
}

Answer 2

if (int.TryParse(...))
    BidMethod(entryInt, MIN);
else if (double.TryParse(...))
    BidMethod(entryDouble, MIN);
...
...

调用太多重载方法 - 只需要一个

2 个答案: