初學者使用C＃驗證數字和字母

Question

我是C＃的新手，無法弄清楚如何在已經編寫的代碼中進行驗證。 我的代碼可以完美運行，但是想要繼續添加功能。 我正在尋找提示或您想提的任何東西。 提前謝謝。 這是我到目前為止的代碼，需要對綠色注釋附近的3個getInputs進行驗證。

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

數值類型具有TryParse方法，可用於捕獲非法輸入。

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.

這是驗證字符串是否為數字的方法：

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

TryParse將返回false，如果字符串無法成功解析出一個有效的整數，並且，如果它成功的解析，將在輸出參數返回轉換INT。

或者，如果您想允許小數：

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.

這是計算字符串中非字母的字符數的方法 ：

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

要確保字符串僅包含字母，只需確保numberOfNonLetters為零