c#实现写入，读取实现百度搜索框

        //写入内容

        private void write(TextBox textBox)

        {

            if (!File.Exists(path))

            {

                FileStream fs = new FileStream(path, FileMode.Create, FileAccess.Write);

                StreamWriter sw = new StreamWriter(fs);

                sw.Write("\r\n" + textBox.Text);

                sw.Flush();

                sw.Close();

                fs.Close();

            }

            else

            {

                FileStream fs = new FileStream(path ,FileMode.Append, FileAccess.Write);

                StreamWriter sw = new StreamWriter(fs);

                sw.Write("\r\n" + textBox.Text);

                sw.Flush();

                sw.Close();

                fs.Close();

            }

        }

        string[] s = new string[] { };

        //绑定文本

        public void bindTxt(TextBox textBox)

        {

            List<string> a = s.ToList();

            StreamReader sr = new StreamReader(path, Encoding.UTF8);

            string line;

            while ((line = sr.ReadLine()) != null)

            {

                a.Add(line);

            }

            s = a.ToArray();

            var source = new AutoCompleteStringCollection();

            source.AddRange(s);

            textBox.AutoCompleteCustomSource = source;

            textBox.AutoCompleteMode = AutoCompleteMode.SuggestAppend;

            textBox.AutoCompleteSource = AutoCompleteSource.CustomSource;

            sr.Close();
        }

private void button1_Click_1(object sender, EventArgs e)

        {

            if (!File.Exists(path))

            {

                write(textBox1);

            }

            else

            {

                StreamReader sr = new StreamReader(path, Encoding.UTF8);

                bool isWirte = true;

                string line1;

                while ((line1 = sr.ReadLine()) != null)

                {

                    if (line1 == textBox1.Text)

                    {

                        isWirte = false;

                        sr.Close();

                        break;

  
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                  }

                }

                if (isWirte)

                {

                    sr.Close();

                    write(textBox1);

                }

                sr.Close();

                bindTxt(textBox1);

            }

        }

    }

}