C#使用正则表达式实现常见的格式验证
作者:wenchm
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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