read/write textfile in windows application...........

private void file_write()
        {
            string path = "C:\\Users\\Techsoft\\Desktop\\textbox\\text2";           
            string ext = ".txt";
            string fname = path + ext;
            
            
            FileInfo file1 = new FileInfo(fname);
            StreamWriter sw = file1.CreateText();
            sw.WriteLine(richTextBox1.Text);

            sw.Close();
        }

        private void file_read()
        {
            string path = "C:\\Users\\Techsoft\\Desktop\\textbox\\text";           
            string name = richTextBox1.Text;
            string ext = ".txt";
            string fname = path + name + ext;
            string readcontent;

            FileInfo file1 = new FileInfo(fname);

            StreamReader sr = new StreamReader(fname);
            readcontent = sr.ReadToEnd(); 	    
            sr.Close();
            richTextBox1.Text = readcontent;             
        }
        private void Form1_Load(object sender, EventArgs e)
        {

        }

        private void button1_Click(object sender, EventArgs e)
        {
            file_read();

        }

        private void button2_Click(object sender, EventArgs e)
        {
            file_write();
        }