我明白了。我用Google搜索了这个问题，发现有这个问题可以使用：
option = Convert.ToChar（Console.ReadKey（true）.KeyChar）;
我已经谷歌搜索和故障排除了好几天。我想让这个计算器程序在操作员选择一个函数（+，-，*，/）后立即返回一个值。从阅读和其他示例看，这ConsoleKeyInfo应该有效：
ConsoleKeyInfo info = Console.ReadKey（）;
string operation = info.Key.ToString（）;
当我添加它时，我无法使程序正常运行。我明白了：
system.formatexception string must exactly be one character long
My current code works, but once you select a function (+), you then have to press enter to get the answer.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ConsoleApp5
{
class Program
{
static void Main(string[] args)
{
int Num1, Num2, result;
char option;
Console.Write("Enter the First Number : ");
Num1 = Convert.ToInt32(Console.ReadLine());
Console.Write("Enter the Second Number : ");
Num2 = Convert.ToInt32(Console.ReadLine());
Console.WriteLine("Select: +, -, *, /");
option = Convert.ToChar(Console.ReadLine());
switch (option)
{
case '+':
result = Num1 + Num2;
Console.WriteLine("The result of Addition is : {0}", result);
break;
case '-':
result = Num1 - Num2;
Console.WriteLine("The result of Subtraction is : {0}", result);
break;
case '*':
result = Num1 * Num2;
Console.WriteLine("The result of Multiplication is : {0}", result);
break;
case '/':
result = Num1 / Num2;
Console.WriteLine("The result of Division is : {0}", result);
break;
default:
Console.WriteLine("Invalid Option");
break;
}
Console.ReadLine();
}
}
}
**