c# - 不能声明局部变量名称 'choice'，因为它会给 'choice' 不同的含义

Question

抱歉，我是编程界的新手。我正在创建一个控制台应用程序，它基本上会根据您的输入来确定您是想将摄氏温度转换为华氏温度，还是相反。

我遇到的问题是:

"Error 3 A local variable named 'choice' cannot be declared in this scope because it would give a different meaning to 'choice', which is already used in a 'parent or current' scope to denote something else"

我尝试查看其他示例，但它们远比我的大脑现在能够理解的复杂得多。

namespace TemperatureApp
{
    class Program
    {
        static void Main(string[] args)
        {
            int choice;

            do
            {
                Console.WriteLine("Hi! This is a temperatue app");
                Console.WriteLine("Press 1 for C to F or 2 for F to C");
                //take the user input
                int choice = Convert.ToInt32(Console.ReadLine());


                if (choice == 1)
                {
                    Console.WriteLine("Great, you chose C to F. Now enter the temp.");
                    int celcius = Convert.ToInt32(Console.ReadLine());
                    //next line use the formula and show answer
                }
                if (choice == 2)
                {
                    Console.WriteLine("Great, you chose F to C. Now enter the temp.");
                    int fahrenheit = Convert.ToInt32(Console.ReadLine());
                    //next line use the formula and show answer
                }
                else
                    Console.WriteLine("That is not the right choice.");
                    //In this way, keep asking the person for either 1 or two

            }
            while (choice != 1 || choice != 2);

            Console.ReadLine();
        }
    }
}

Answer 1

int choice = Convert.ToInt32(Console.ReadLine());

应该阅读

choice = Convert.ToInt32(Console.ReadLine());

通过将 int 放入第二次，您在 {} 中声明了另一个名为“choice”的变量。该定义与外部的定义相冲突。