验证两个文本框(C#)

using System;
using System.Text.RegularExpressions;

class Program
{
    static void Main()
    {
        string email = "example@example.com";
        string pattern = @"^[a-zA-Z0-9_.+-]+@[a-zA-Z0-9-]+\.[a-zA-Z0-9-.]+$";

        if (Regex.IsMatch(email, pattern))
        {
            Console.WriteLine("邮箱地址有效");
        }
        else
        {
            Console.WriteLine("邮箱地址无效");
        }
    }
}

using System;

class Program
{
    static void Main()
    {
        string input = "12345";
        int number;

        if (int.TryParse(input, out number))
        {
            Console.WriteLine("输入的是一个整数");
        }
        else
        {
            Console.WriteLine("输入的不是一个整数");
        }
    }
}