write to file

using System.IO; 

               FileStream fs1 = new FileStream(Application.StartupPath + "\\text.txt", FileMode.Create, FileAccess.Write);//创建写入文件  
                StreamWriter sw = new StreamWriter(fs1，Encoding.GetEncoding("utf-8"))　// 加上Encoding.GetEncoding("utf-8")解决乱码
                sw.WriteLine("[runtype]");//开始写入值              
                sw.WriteLine("type=1");
                sw.Close();
                fs1.Close();