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C#使用正则表达式实现常见的格式验证

作者:wenchm

这篇文章主要为大家详细介绍了C#如何使用正则表达式实现常见的格式验证,例如:电话号码、密码、邮编等,感兴趣的小伙伴可以跟随小编一起学习一下

正则表达式在程序设计中有着重要的位置,经常被用于处理字符串信息。

用Regex类的IsMatch方法,使用正则表达式可以验证电话号码是否合法。

一、涉及到的知识点

Regex类的IsMatch方法用于指示正则表达式使用pattern参数中指定的正则表达式是否在输入字符串中找到匹配项。语法格式如下:

public static bool IsMatch(string input,string patterm)

参数说明

Input:字符串对象,表示要搜索匹配项的字符串。

Pattern:字符串对象,表示要匹配的正则表达式模式。

Bool:返回布尔值,如果正则表达式找到匹配项,则返回值为true,否则返回值为false。

其中,正则表达式中匹配位置的元字符“^”。正则表达式中“^”用于匹配行首,如果正则表达式匹配以First开头的行,则正则表达式如下:^First。

如果电话号码的格式:xxx-xxxxxxxx,其中,x—代表数字,那么匹配的正则表达式是:^(\d{3,4}-)?\d{6,8}$。

如果密码有a-z、A-Z、0-9组成,并且至少一个大小写字母和数字,那么其正则表达式:[A-Za-z]+[0-9];

如果密码有a-z、A-Z、0-9组成,并且至少一个大小写字母或数字,那么其正则表达式:[A-Za-z0-9]+,其中+有没有都可以;

如果把正则表达式改为[A-Z]+[a-z]+[0-9],就变成依次至少一个大写、一个小写、一个数字了,打乱了顺序都不行。

由6位数字组成的邮编的正则表达式:^\d{6}$;

二、实例1:验证电话号码的格式

//使用正则表达式验证电话号码
namespace _070
{
    public partial class Form1 : Form
    {
        private Label? label1;
        private Label? label2;
        private Label? label3;
        private Button? button1;
        private TextBox? textBox1;
        public Form1()
        {
            InitializeComponent();
            Load += Form1_Load;
        }
        private void Form1_Load(object? sender, EventArgs e)
        {
            // 
            // label1
            // 
            label1 = new Label
            {
                AutoSize = true,
                Location = new Point(36, 22),
                Name = "label1",
                Size = new Size(68, 17),
                TabIndex = 0,
                Text = "输入号码:"
            };
            // 
            // label2
            //        
            label2 = new Label
            {
                AutoSize = true,
                Location = new Point(156, 49),
                Name = "label2",
                Size = new Size(79, 17),
                TabIndex = 1,
                Text = "xxx-xxxxxxxx"
            };
            // 
            // label3
            //          
            label3 = new Label
            {
                AutoSize = true,
                Location = new Point(36, 49),
                Name = "label3",
                Size = new Size(68, 17),
                TabIndex = 2,
                Text = "号码格式:"
            };
            // 
            // button1
            //         
            button1 = new Button
            {
                Location = new Point(160, 76),
                Name = "button1",
                Size = new Size(75, 23),
                TabIndex = 3,
                Text = "号码验证",
                UseVisualStyleBackColor = true
            };
            button1.Click += Button1_Click;
            // 
            // textBox1
            // 
            textBox1 = new TextBox
            {
                Location = new Point(115, 16),
                Name = "textBox1",
                Size = new Size(120, 23),
                TabIndex = 4
            };
            // 
            // Form1
            // 
            AutoScaleDimensions = new SizeF(7F, 17F);
            AutoScaleMode = AutoScaleMode.Font;
            ClientSize = new Size(294, 111);
            Controls.Add(textBox1);
            Controls.Add(button1);
            Controls.Add(label3);
            Controls.Add(label2);
            Controls.Add(label1);
            Name = "Form1";
            StartPosition = FormStartPosition.CenterScreen;
            Text = "使用正则表达式验证电话号码";
          
        }
        /// <summary>
        /// 验证电话号码格式是否正确
        /// </summary>
        private void Button1_Click(object? sender, EventArgs e)
        {
            if (!IsTelephone(textBox1!.Text))
            { 
                MessageBox.Show("电话号码格式不正确"); 
            }
            else 
            { 
                MessageBox.Show("电话号码格式正确"); 
            }
        }
 
        /// <summary>
        /// 验证电话号码格式是否匹配
        /// </summary>
        /// <param name="str_telephone">电话号码信息</param>
        /// <returns>方法返回布尔值</returns>
        public static bool IsTelephone(string str_telephone)
        {
            return MyRegex().IsMatch(str_telephone);
        }
 
        [System.Text.RegularExpressions.GeneratedRegex(@"^(\d{3,4}-)?\d{6,8}$")]
        private static partial System.Text.RegularExpressions.Regex MyRegex();
    }
}

三、实例2:验证密码的格式

// 使用正则表达式验证密码格式
namespace _071
{
    public partial class Form1 : Form
    {
        private GroupBox? groupBox1;
        private Button? button1;
        private TextBox? textBox1;
        private Label? label1;
 
        public Form1()
        {
            InitializeComponent();
            Load += Form1_Load;
        }
        private void Form1_Load(object? sender, EventArgs e)
        {
            // 
            // button1
            // 
            button1 = new Button
            {
                Location = new Point(171, 58),
                Name = "button1",
                Size = new Size(100, 23),
                TabIndex = 2,
                Text = "验证密码格式",
                UseVisualStyleBackColor = true
            };
            button1.Click += Button1_Click;
            // 
            // textBox1
            // 
 
            textBox1 = new TextBox
            {
                Location = new Point(126, 24),
                Name = "textBox1",
                Size = new Size(145, 23),
                TabIndex = 1
            };
            // 
            // label1
            //
 
            label1 = new Label
            {
                AutoSize = true,
                Location = new Point(35, 30),
                Name = "label1",
                Size = new Size(68, 17),
                TabIndex = 0,
                Text = "输入密码:"
            };
            // 
            // groupBox1
            // 
            groupBox1 = new GroupBox
            {
                Location = new Point(12, 12),
                Name = "groupBox1",
                Size = new Size(307, 87),
                TabIndex = 0,
                TabStop = false,
                Text = "密码必须由数字和大小写字母组成"
            };
            groupBox1.Controls.Add(button1);
            groupBox1.Controls.Add(textBox1);
            groupBox1.Controls.Add(label1);
            groupBox1.SuspendLayout();
 
            // 
            // Form1
            // 
            AutoScaleDimensions = new SizeF(7F, 17F);
            AutoScaleMode = AutoScaleMode.Font;
            ClientSize = new Size(331, 111);
            Controls.Add(groupBox1);
            Name = "Form1";
            StartPosition = FormStartPosition.CenterScreen;
            Text = "正则表达式验证密码格式";
            groupBox1.ResumeLayout(false);
            groupBox1.PerformLayout();
        }
 
        private void Button1_Click(object? sender, EventArgs e)
        {
            if (!IsPassword(textBox1!.Text.Trim()))
            { 
                MessageBox.Show("密码格式不正确!!!"); 
            }
            else
            {
                MessageBox.Show("密码格式正确!!!!!");
            }
        }
        /// <summary>
        /// 验证码码输入条件
        /// </summary>
        /// <param name="str_password">密码字符串</param>
        /// <returns>返回布尔值</returns>
        public static bool IsPassword(string str_password)
        {
            return MyRegex().IsMatch(str_password);
        }
 
        [System.Text.RegularExpressions.GeneratedRegex(@"[A-Za-z]+[0-9]")]//至少有一个字母,至少有一个数字
        //[System.Text.RegularExpressions.GeneratedRegex(@"[A-Z]+[a-z]+[0-9]")]//依次至少有一个大写一个小写一个
        //[System.Text.RegularExpressions.GeneratedRegex(@"[A-Za-z0-9]+")]//至少一个
        private static partial System.Text.RegularExpressions.Regex MyRegex();
    }
}

四、实例3:验证邮编的格式

// 用正则表达式验证邮编合法性
namespace _072
{
    public partial class Form1 : Form
    {
        private GroupBox? groupBox1;
        private TextBox? textBox1;
        private Button? button1;
        private Label? label1;
 
        public Form1()
        {
            InitializeComponent();
            Load += Form1_Load;
        }
        private void Form1_Load(object? sender, EventArgs e)
        {
            // 
            // textBox1
            // 
            textBox1 = new TextBox
            {
                Location = new Point(139, 32),
                Name = "textBox1",
                Size = new Size(100, 23),
                TabIndex = 2
            };
            // 
            // button1
            // 
            button1 = new Button
            {
                Location = new Point(139, 61),
                Name = "button1",
                Size = new Size(100, 23),
                TabIndex = 1,
                Text = "验证邮编",
                UseVisualStyleBackColor = true
            };
            button1.Click += Button1_Click;
            // 
            // label1
            // 
            label1 = new Label
            {
                AutoSize = true,
                Location = new Point(55, 35),
                Name = "label1",
                Size = new Size(68, 17),
                TabIndex = 0,
                Text = "输入邮编:"
            };
            // 
            // groupBox1
            // 
            groupBox1 = new GroupBox
            {
                Location = new Point(12, 12),
                Name = "groupBox1",
                Size = new Size(280, 98),
                TabIndex = 0,
                TabStop = false,
                Text = "验证邮编格式:"
            };
            groupBox1.Controls.Add(textBox1);
            groupBox1.Controls.Add(button1);
            groupBox1.Controls.Add(label1);
            groupBox1.SuspendLayout();
            // 
            // Form1
            // 
            AutoScaleDimensions = new SizeF(7F, 17F);
            AutoScaleMode = AutoScaleMode.Font;
            ClientSize = new Size(304, 122);
            Controls.Add(groupBox1);
            Name = "Form1";
            StartPosition = FormStartPosition.CenterScreen;
            Text = "验证邮编格式合法性";
            groupBox1.ResumeLayout(false);
            groupBox1.PerformLayout();
        }
 
        private void Button1_Click(object? sender, EventArgs e)
        {
            if (!IsPostalcode(textBox1!.Text))
            { 
                MessageBox.Show("邮政编号不正确!!!"); 
            }
            else 
            {
                MessageBox.Show("邮政编号正确!!!!!"); 
            }
        }
        /// <summary>
        /// 验证邮编格式是否正确
        /// </summary>
        /// <param name="str_postalcode">邮编字符串</param>
        /// <returns>返回布尔值</returns>
        public static bool IsPostalcode(string str_postalcode)
        {
            return MyRegex().IsMatch(str_postalcode);
        }
 
        [System.Text.RegularExpressions.GeneratedRegex(@"^\d{6}$")]
        private static partial System.Text.RegularExpressions.Regex MyRegex();
    }
}

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