c# - 如何同时读入文件和修改文件？

Question

我想用 C# 编程，读取这样的文件:

...

辛迪辛迪0辛迪1辛迪2辛迪3

miao miao0 miao1 miao2 miao3

...

我想在第一行的末尾添加类似“cindy4”的内容。

System.IO.StreamReader file = new System.IO.StreamReader(filename);
string line = file.ReadLine();
while(line != null)
{
    if (line.Contains("cindy"))
    {
         tmp = line.Split(' ');
         file.Close();

         //TO DO change in the file

         break;
     }
     line = file.ReadLine();
}

在 TODO 部分，我这样编码:

System.IO.StreamWriter writer = new System.IO.StreamWriter(System.IO.File.Open(filename, System.IO.FileMode.Open));
writer.Write("cindy4");
writer.Flush();

但它不起作用。有人可以给我举个例子吗？

Answer 1

试试这段代码:

string[] new_text = System.IO.File.ReadAllLines("file_path");
new_text[line_number] += "text_to_add"; 
//the line number start from zero 
//Example: first line will be: new_text[0]
//the second line will be: new_text[1]
//Etc...
System.IO.File.WriteAllLines("file_path",new_text);