C# 中的 System.FormatException

在我尝试为 sale 变量分配值的行中的每种情况下，我不断收到 FormatException。有人知道我做错了什么吗？我应该将此控制台程序作为学习循环的作业，但我正在了解更多有关其他内容的信息。它应该根据每笔销售的 10% 佣金来记录销售人员的佣金。无论如何，这是代码：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace TubSales
{
   class Program
   {
      static void Main(string[] args)
      {
         char initial;
         const double COMM_INT = 0.10;
         double sale, aComm = 0, bComm = 0, eComm = 0;
         Console.Write("Enter 'A' for Andrea, 'B' for Brittany,\n'E' for Eric, or 'Z' to quit >> ");
         initial = Convert.ToChar(Console.Read());
         while (initial != 'z' && initial != 'Z')
         {
            switch (initial)
            {
               case 'a':
               case 'A':
                  Console.Write("Enter the sales for Andrea >> ");
                  sale = Convert.ToDouble(Console.ReadLine());
                  aComm = aComm + COMM_INT * sale;
                  break;
               case 'b':
               case 'B':
                  Console.Write("Enter the sales for Brittany >> ");
                  sale = Convert.ToDouble(Console.ReadLine());
                  bComm = bComm + COMM_INT * sale;
                  break;
               case 'e':
               case 'E':
                  Console.Write("Enter the sales for Eric >> ");
                  sale = Convert.ToDouble(Console.ReadLine());
                  eComm = eComm + COMM_INT * sale;
                  break;
               default:
                  Console.WriteLine("You did not enter a valid initial");
                  break;
            }
            Console.Write("Enter 'A' for Andrea, 'B' for Brittany, or 'E' for Eric >> ");
            initial = (char)Console.Read();
         }
         Console.WriteLine("Andrea had {0}, Brittany had {1}, and Eric had {2} in commissions.", aComm.ToString("C"), bComm.ToString("C"), eComm.ToString("C"));
         Console.Write("Press any key to exit... ");
         Console.ReadKey();
      }
   }
}

在我尝试为 sale 变量分配值的行中的每种情况下，我不断收到 FormatException。有人知道我做错了什么吗？

The 转换为双精度 http://msdn.microsoft.com/en-us/library/zh1hkw6k.aspx方法会提出一个FormatException如果字符串（从返回Console.ReadLine()) 不是有效数字。

通常，如果您想解析用户输入，最好使用Double.TryParse http://msdn.microsoft.com/en-us/library/system.double.tryparse.aspx相反，因为这可以让您确定输入是否是有效数字without捕获异常。

这通常看起来像这样：

Console.Write("Enter the sales for Andrea >> ");
while (!double.TryParse(Console.ReadLine(), out sale))
{
    Console.WriteLine("Value entered was not a valid number.");
    Console.Write("Enter the sales for Andrea >> ");
}
// Once you get here, "sale" will be set appropriately