c# - 确保文本框的第一个和最后一个字符是数字c#

Question

我目前正在创建一个 Windows 窗体，该窗体必须仅在符合特定条件时才允许密码通过。我快要完成了，但是我有点被一个元素困住了。 “密码的第一个和最后一个字符必须是数字”。

查看我当前的代码，我将如何解决这个问题，因为我的想法为零。所以婴儿的步骤和耐心将不胜感激。

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Text.RegularExpressions;

namespace password_test
{
    public partial class Form1 : Form
    {

        bool Finished = false;


        private bool TestPassword(string passwordText, int minimumLength =     5, int maximumLength = 12, int minimumNumbers = 1, int minimumLetters = 1)
    {


        int letters = 0;
        int digits = 0;
        int minLetters = 0;


        if (passwordText.Length < minimumLength)
        {
            MessageBox.Show("You must have at least " + minimumLength + " characters in your password.");
            return false;
        }

        if (passwordText.Length > maximumLength)
        {
            MessageBox.Show("You must have no more than " + maximumLength + " characters in your password.");
            return false;
        }

        foreach (var ch in passwordText)
        {
            if (char.IsLetter(ch)) letters++; 
            if (char.IsDigit(ch)) digits++; 

            if (ch > 96 && ch < 123)
            {
                minLetters++;
            }
        }


        if (digits < minimumNumbers)
        {
            MessageBox.Show("You must have at least " + minimumNumbers + " numbers in your password.");
            return false;
        }

        if (minLetters < minimumLetters)
        {
            MessageBox.Show("You must have at least " + minimumLetters + " letter in your password");
            return false;
        }
        Finished = true;
        return true;


    }


    public Form1()
    {
        InitializeComponent();
    }


    private void textBox1_TextChanged(object sender, EventArgs e)
    {

    }

    private void Form1_Load(object sender, EventArgs e)
    {

    }

    private void butConfirm_Click(object sender, EventArgs e)
    {





        if (txtPassword.Text == txtRetypePassword.Text)
        {
                bool temp = TestPassword(txtPassword.Text, 10, 100, 1, 1);


            if (Finished == true)
            {
                MessageBox.Show("Password Accepted");
                Application.Exit();
                //this.Hide();
                //Form2 f2 = new Form2();
                //f2.ShowDialog();

            }
        }


        else
        {
            MessageBox.Show("Please ensure the passwords you have typed match");
            return;
        }


    }

    private void txtPassword_KeyPress(object sender, KeyPressEventArgs e)
    {
        if (!char.IsControl(e.KeyChar) && !char.IsLetterOrDigit(e.KeyChar))
        {
            e.Handled = true;
        }
        else
        {
            return;
        }
    }

    private void txtRetypePassword_TextChanged(object sender, EventArgs e)
    {

    }




}
} 

Answer 1

在 Finished = true; 之前，您可以简单地进行检查:

if (!char.IsDigit(passwordText[0]) || !char.IsDigit(passwordText[passwordText.Length - 1])) 
{
    MessageBox.Show("The first and last characters of the password  have to be numbers");
    return false;   
}
Finished = true;

您还应该在您的方法中强制执行最小长度。