嵌套while语句上的无限循环

Question

我正在尝试将 2 个 while 循环用于 C# 控制台程序。外部是重复程序菜单和功能，直到用户退出。我用作验证用户输入的内部循环（需要将其解析为 int）。

内部循环似乎工作正常，但是一旦程序到达 switch 语句，它似乎会无休止地循环 switch 条件。因此，一旦我相信外部 while 循环使其无休止地写入，而不是写入控制台。只有将标志设置为假的情况才会按预期停止。

有人可以解释发生了什么吗？我将如何更新标志以使外部 while 循环不会无休止地执行开关中的功能？程序应返回用户菜单并在所有情况下等待输入，除非用户选择 7 结束程序。我已经盯着这个看了好几个小时了。请指教！

using System;
using static System.Console;
using System.Collections.Generic;

namespace Project02AreaCalculator
{
  class Program
  {
    static private bool flag = true;
    static void Main(string[] args)
    {

        string inputvalue = "";
        int caseSwitch;

        // repeat program until flag is set to false by user selecting 7 to exit
        do
        {
            // repeat menu until user input can be parsed into an integer
            while (!int.TryParse(inputvalue, out caseSwitch))
            {
                flag = false;
                Console.WriteLine("Shape Area Calculator");
                Console.WriteLine("******************************************");
                Console.WriteLine("\t1. Circle");
                Console.WriteLine("\t2. Square");
                Console.WriteLine("\t3. Rectangle");
                Console.WriteLine("\t4. Rhombus");
                Console.WriteLine("\t5. Parallelogram");
                Console.WriteLine("\t6. Trapezoid");
                Console.WriteLine("\t7. Exit");
                Console.WriteLine("******************************************");
                Console.WriteLine("Select a shape type to calculate");
                inputvalue = ReadLine();
            }

            //convert input to integer and assign to caseSwitch
            caseSwitch = Convert.ToInt32(inputvalue);

            switch (caseSwitch)
            {
                case 1:
                    CalculateCircle();
                    //Clear();
                    flag = true;
                    break;
                case 2:
                    CalculateSquare();
                    // Clear();
                    flag = true;
                    break;
                case 3:
                    CalculateRectangle();
                    //Clear();
                    flag = true;
                    break;
                case 4:
                    CalculateRhombus();
                    //Clear();
                    flag = true;
                    break;
                case 5:
                    CalculateParallelogram();
                    //Clear();
                    flag = true;
                    break;
                case 6:
                    CalculateTrapezoid();
                    //Clear();
                    flag = true;
                    break;
                case 7:
                    //Clear();
                    Console.WriteLine("Goodbye! Press any key to end");
                    ReadKey();
                    flag = false;
                    break;
                default:
                    // Clear();
                    Console.WriteLine("Invalid Selection, Select 1-7");
                    flag = true;
                    break;
            }


        } while (caseSwitch != 7);

    }//end main

        //****************METHODS SECTION ****************************************************************************
        static private void CalculateCircle()
        {
            //area = pi * radius * radius (or pi times radius squared)
            Console.Clear();
            Console.WriteLine("Circle Area Calculator");
            Console.WriteLine("Enter the length of the circle's radius (-1 to exit back to menu):");
            Console.ReadKey();

        }
        static private void CalculateSquare()
        {
            //area = side * side (or side squared)
            Console.Clear();
            Console.WriteLine("Square Area Calculator");
            Console.WriteLine("Enter the length of one side of the square (-1 to exit back to menu):");
            Console.ReadKey();
          }
        static private void CalculateRectangle()
        {
            //area = Length * Width
            Console.Clear();
            Console.WriteLine("Rectangle Area Calculator");
            Console.WriteLine("Enter the length of one side of the Rectangle (-1 to exit back to menu):");
            Console.WriteLine("Enter the length of an opposing side of the Rectangle (-1 to exit back to menu):");
            Console.ReadKey();
        }

        static private void CalculateRhombus()
        {
            //area = ½ a * b (a and b being diagonals)
            Console.Clear();
            Console.WriteLine("Rhombus Area Calculator");
            Console.WriteLine("Enter the length of one diagonal of the rhombus (-1 to exit back to menu):");
            Console.WriteLine("Enter the length of the other diagonal of the rhombus (-1 to exit back to menu):");
            Console.ReadKey();
         }
        static private void CalculateParallelogram()
        {
            //area = base * height
            Console.WriteLine("Parallelogram Area Calculator");
            Console.WriteLine("Enter the length of the base of the Parallelogram (-1 to exit back to menu):");
            Console.WriteLine("Enter the height of the Parallogram (-1 to exit back to menu):");
            Console.ReadKey();
         }

        static private void CalculateTrapezoid()
        {
            //area = ½ height * (largeBase + smallBase)
            Console.WriteLine("Trapezoid Area Calculator"); 
            Console.ReadKey();
         }
    }
}

Answer 1

只是为了让您的程序运行，请执行以下更改，

在检查用户输入之前重置 inputvalue 和 caseSwitch 的值，如下所示，

...
...
do
            {
                inputvalue = "";
                caseSwitch = 0;
                // repeat menu until user input can be parsed into an integer
                while (!int.TryParse(inputvalue, out caseSwitch))
                {
...
...

而且，下面的语句也不是必需的

caseSwitch = Convert.ToInt32(inputvalue);

其他问题是，

在所有函数中，它都要求用户输入，但输入没有被使用或存储在任何变量中。

即使在CalculateParallelogram、CalculateRhombus 等某些函数中，用户也被要求输入两个值length 和height，并且只接受一个输入，而且该输入也是单个键（Console.ReadKey()）。

所以将 ReadKey 更改为 ReadLine 并在被询问的地方接受两个输入。 此代码中还有其他逻辑问题需要改进。

Answer 2

尝试添加

inputvalue="";

之后

caseSwitch = Convert.ToInt32(inputvalue);