急！！！C#文件数据写入
string[] lines = File.ReadAllLines(path, Encoding.GetEncoding("GB2312"));
lines[2]=lines[2].Substring(0,13)+ Str;
用ReadAllLines方法取出的数据修改后要怎么写回原来的地方？

------解决方案--------------------
File.WriteAllLines(path, lines, Encoding.GetEncoding("GB2312"));