private void button1_Click(object sender, EventArgs e)
        {
            FolderBrowserDialog P = new FolderBrowserDialog();
            if (P.ShowDialog()==DialogResult.OK)
            {
                File.Create(P.SelectedPath+"\\"+Guid.NewGuid().ToString()+".txt");
            }
        }

        private void button2_Click(object sender, EventArgs e)
        {
             FolderBrowserDialog P = new FolderBrowserDialog();
            if (P.ShowDialog()==DialogResult.OK)
            {
                Directory.CreateDirectory(P.SelectedPath+"\\"+Guid.NewGuid().ToString());
            }
        }

隨機產生文件名稱