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;

namespace WindowsFormsTextBox
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            textBox1.Multiline = true;  //设置文本框为多行文本框
            //textBox1.Text = "作业星辰昨夜风，画楼西畔桂堂东。身无彩凤双飞翼，心有灵犀一点通。";
            //textBox1.Height = 100;  //设置文本框的高度
            textBox1.SelectionStart = 5;    //开始选择的起始位置，从0开始
            textBox1.SelectionLength = 5;   //选择的长度
        }

        private void textBox1_TextChanged(object sender, EventArgs e)
        {
            label1.Text = textBox1.Text;
        }

    }
}