C#利用正则表达式实现获取字符串中汉字的数量

Regex regex = MyRegex();                //创建正则表达式对象，用于判断字符是否为汉字
[GeneratedRegex("^[\u4E00-\u9FA5]{0,}$")]
private static partial Regex MyRegex();

// 用正则表达式获取字符串中汉字的个数
using System.Text.RegularExpressions;
namespace _044
{
    public partial class Form1 : Form
    {
        private GroupBox? groupBox1;
        private TextBox? textBox2;
        private TextBox? textBox1;
        private Button? button1;
        private Label? label2;
        private Label? label1;
 
        public Form1()
        {
            InitializeComponent();
            Load += Form1_Load;
        }
        private void Form1_Load(object? sender, EventArgs e)
        {
            // 
            // textBox2
            // 
            textBox2 = new TextBox
            {
                Location = new Point(117, 48),
                Name = "textBox2",
                Size = new Size(133, 23),
                TabIndex = 4,
            };
            // 
            // textBox1
            // 
            textBox1 = new TextBox
            {
                Location = new Point(117, 18),
                Name = "textBox1",
                Size = new Size(162, 23),
                TabIndex = 3
            };
            // 
            // button1
            // 
            button1 = new Button
            {
                Location = new Point(17, 48),
                Name = "button1",
                Size = new Size(97, 23),
                TabIndex = 2,
                Text = "获取汉字数量",
                UseVisualStyleBackColor = true
            };
            button1.Click += Button1_Click;
            // 
            // label2
            // 
            label2 = new Label
            {
                AutoSize = true,
                Location = new Point(259, 50),
                Name = "label2",
                Size = new Size(20, 17),
                TabIndex = 1,
                Text = "个"
            };
            // 
            // label1
            //         
            label1 = new Label
            {
                AutoSize = true,
                Location = new Point(17, 24),
                Name = "label1",
                Size = new Size(80, 17),
                TabIndex = 0,
                Text = "输入字符串："
            };
            // 
            // groupBox1
            //           
            groupBox1 = new GroupBox
            {
                Location = new Point(12, 12),
                Name = "groupBox1",
                Size = new Size(285, 77),
                TabIndex = 0,
                TabStop = false,
                Text = "获取汉字数量"
            };
            groupBox1.Controls.Add(textBox2);
            groupBox1.Controls.Add(textBox1);
            groupBox1.Controls.Add(button1);
            groupBox1.Controls.Add(label2);
            groupBox1.Controls.Add(label1);
            groupBox1.SuspendLayout();
            
            // 
            // Form1
            // 
            AutoScaleDimensions = new SizeF(7F, 17F);
            AutoScaleMode = AutoScaleMode.Font;
            ClientSize = new Size(309, 101);
            Controls.Add(groupBox1);
            Name = "Form1";
            StartPosition = FormStartPosition.CenterScreen;
            Text = "获取字符串中汉字的数量";         
            groupBox1.ResumeLayout(false);
            groupBox1.PerformLayout();
        }
 
        private void Button1_Click(object? sender, EventArgs e)
        {
            int temp = 0;                                  //用于存储汉字数量
            Regex regex = MyRegex();                       //创建正则表达式对象，用于判断字符是否为汉字
 
            for (int i = 0; i < textBox1!.Text.Length; i++)//遍历字符串中每一个字符
            {
                temp = regex.IsMatch(textBox1.Text[i].     //如果字符是汉字则计数器加1
                    ToString()) ? ++temp : temp;
            }
            textBox2!.Text = temp.ToString();              //显示汉字数量
        }
 
        [GeneratedRegex("^[\u4E00-\u9FA5]{0,}$")]
        private static partial Regex MyRegex();
    }
}