初学者使用C#验证数字和字母

本文关键字：数字 验证 初学者 | 更新日期: 2023-09-27 18:20:14

我是C#的新手，不知道如何在我已经编写的代码中进行验证。我的代码运行得很完美，但我想继续添加功能。我在找小费或任何你想提及的东西。提前谢谢。这是我迄今为止拥有的代码，需要对绿色注释附近的3个getInputs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();
        }
    }
}

初学者使用C#验证数字和字母

数字类型有一个TryParse方法，可以用来捕获非法输入。

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.");
}

//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，则将在out参数中返回转换后的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

相同的想法

//Validate name to be a string of letters.

以下是如何计算字符串中而非字母的字符数：

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

要确保字符串只有字母，只需确保numberOfNonLetters为零即可。

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