Question

我是C＃的新手，无法弄清楚如何在我已编写的代码中进行验证。我有完美的代码，但想继续添加功能。我正在寻找你需要提及的提示或任何内容。提前谢谢。 这是我到目前为止的代码，需要在绿色评论附近的3个getInputs上进行验证。

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

namespace BasicUserInterface
{
    class Program
    {
        static void DisplayApplicationInformation()
        {
            Console.WriteLine("Welcome to the Basic User Interface Program");
            Console.WriteLine("CIS247, Week 2 Lab");
            Console.WriteLine("Name: Fred Ziyad");
            Console.WriteLine();
            Console.WriteLine("This program accepts user input as a string, then makes the");
            Console.WriteLine("approppriate data conversion and display the results.");
            Console.WriteLine();
        }

        static void DisplayDivider(String outputTitle)
        {
            Console.WriteLine("************* " + outputTitle + " **************");
        }

        static string GetInput(string inputType)
        {
            string strInput;

            Console.Write("Enter " + inputType + ": ");
            strInput = Console.ReadLine();

            return strInput;
        }

        static void TerminateApplication()
        {
            Console.WriteLine();
            Console.WriteLine("Thank you for using the Basic User Interface program");
            Console.Read();
        }

        static void Main(string[] args)
        {
            int age;
            double mileage;
            string strInput, name;

            DisplayApplicationInformation();

            DisplayDivider("Start Program");
            Console.WriteLine();

            DisplayDivider("Get Name");
            name = GetInput("your name");
            Console.WriteLine("Your name is " + name);
            Console.WriteLine();
            //Validate name to be a string of letters.

            DisplayDivider("Get Age");
            strInput = GetInput("your age");
            age = int.Parse(strInput);
            Console.WriteLine("Your age is: " + age);
            Console.WriteLine();
            //Validate age to be a number.

            DisplayDivider("Get Mileage");
            strInput = GetInput("gas mileage");
            mileage = double.Parse(strInput);
            Console.WriteLine("Your car MPT is: " + mileage);
            //Validate mileage to be a number.

            TerminateApplication();
        }
    }
}

Answer 1

数字类型具有TryParse方法，可用于捕获非法输入。

示例：

DisplayDivider("Get Age");
strInput = GetInput("your age");
if (int.TryParse(strInput, out age)) {
  Console.WriteLine("Your age is: " + age);
  Console.WriteLine();
} else {
  Console.WriteLine("Age input was not a valid number.");
}

Answer 2

//Validate age to be a number.

以下是验证字符串是否为数字的方法：

string str = "123";
int result;
if (!Int32.TryParse(str, out result))
    ; //not a whole number

如果字符串未成功解析为有效整数，则

TryParse将返回false，如果成功解析，则将返回out参数中的转换后的int。

或者如果你想允许小数：

string str = "123.5";
double result;
if (!Double.TryParse(str, out result))
    ; //not a number

同样的想法

//Validate name to be a string of letters.

以下是如何计算字符串中不是字母的字符数：

string str = "AB3C";
int numberOfNonLetters = str.Count(c => !Char.IsLetter(c));

要确保字符串只有字母，请确保numberOfNonLetters为零

使用C＃为初学者验证数字和字母

2 个答案: