?using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

namespace WindowsApplication1
{
    public partial class Form4 : Form
    {
        public Form4()
        {
            InitializeComponent();
        }
        public RichTextBox s1;
        public int start;
        private void button1_Click(object sender, EventArgs e)
        {
            string str1;
            str1 = textBox1.Text;
            if (str1 == "")
            {
                MessageBox.Show("請確認(rèn)查找內(nèi)容！", "異常警示");
            }
            else
            {
                start = s1.Find(str1, start, RichTextBoxFinds.MatchCase);
                if (start == -1)
                {
                    MessageBox.Show("已經(jīng)查到文檔的結(jié)尾！", "結(jié)束查找");
                    start = 0;
                    s1.Focus();

                }
                else
                {
                    start = start + str1.Length;
                    s1.Focus();
                }
            }
        }

        private void button2_Click(object sender, EventArgs e)
        {
            this.Close();
        }

        private void Form4_Load(object sender, EventArgs e)
        {

        }
    }
}