C#使用StringBuilder实现高效处理字符串

StringBuilder P_stringbuilder = new StringBuilder("abc");  //使用new关键字调用构造方法创建对象
P_stringbuilder.Insert(2,Environment.NewLine);             //调用对象的Insert方法向字符串中插入字符

//按标点符号对字符串分行显示
using System.Text;
 
namespace _039
{
    public partial class Form1 : Form
    {
        private GroupBox? groupBox1;
        private TextBox? textBox3;
        private Button? button1;
        private TextBox? textBox1;
        private TextBox? textBox2;
 
        public Form1()
        {
            InitializeComponent();
            Load += Form1_Load;
        }
        private void Form1_Load(object? sender, EventArgs e)
        {
            // 
            // textBox3
            // 
            textBox3 = new TextBox
            {
                Location = new Point(12, 22),
                Multiline = true,
                Name = "textBox3",
                Size = new Size(310, 46),
                TabIndex = 6,
                Text = "在下面文本框中输入字符串，并使用（,）号分隔，点击分行显示按钮，根据（,）号对字符串进行分行。"
            };
            // 
            // button1
            //      
            button1 = new Button
            {
                Location = new Point(130, 170),
                Name = "button1",
                Size = new Size(75, 23),
                TabIndex = 3,
                Text = "分行显示",
                UseVisualStyleBackColor = true
            };
            button1.Click += Button1_Click;
            // 
            // textBox1
            //            
            textBox1 = new TextBox
            {
                Location = new Point(12, 80),
                Multiline = true,
                Name = "textBox1",
                Size = new Size(310, 84),
                TabIndex = 4
            };
            // 
            // textBox2
            //            
            textBox2 = new TextBox
            {
                Location = new Point(12, 200),
                Multiline = true,
                Name = "textBox2",
                Size = new Size(310, 84),
                TabIndex = 5
            };
            // 
            // groupBox1
            //            
            groupBox1 = new GroupBox
            {
                Location = new Point(0, 0),
                Name = "groupBox1",
                Size = new Size(334, 74),
                TabIndex = 0,
                TabStop = false,
                Text = "操作说明："
            };
            groupBox1.Controls.Add(textBox3);
            groupBox1.SuspendLayout();
         
            // 
            // Form1
            // 
            AutoScaleDimensions = new SizeF(7F, 17F);
            AutoScaleMode = AutoScaleMode.Font;
            ClientSize = new Size(334, 296);
            Controls.Add(textBox2);
            Controls.Add(textBox1);
            Controls.Add(button1);
            Controls.Add(groupBox1);
            Name = "Form1";
            StartPosition = FormStartPosition.CenterScreen;
            Text = "按标点符号对字符串分行";
            groupBox1.ResumeLayout(false);
            groupBox1.PerformLayout();
        }
 
        private void Button1_Click(object? sender, EventArgs e)
        {
            StringBuilder stringbuilder = new(textBox1!.Text);      //创建字符串处理对象
            for (int i = 0; i < stringbuilder.Length; i++)
                if (stringbuilder[i] == '，')                       //判断是否出现（,）号
                    stringbuilder.Insert(++i, Environment.NewLine); //向字符串内添加换行符
            textBox2!.Text = stringbuilder.ToString();              //得到分行后的字符串
        }
    }
}