如何使用 StreamWriter 在 c# 中编辑文本文件?

我有一种方法可以编辑文本文件中的单词并将其显示在命令提示符上.现在我尝试制作一种方法来编辑文本文件中的单词并将其写入新文件.我还想提一下，我不能使用 File 或 Regex 类，因为我不允许在我的作业中使用它.这是我的 StreamReader 代码:

I have a method to edit a word from a text file file and display it on the command prompt. Now I an trying to make a method to edit a word from a text file and write it to a new file. I would also like to mention that I cannot use the File or Regex class since I am not allowed to use it for my assignment. Here is my code for the StreamReader:

public void EditorialControl(string fileName, string word, string replacement)
{            
    List<string> list = new List<string>();
    using (StreamReader reader = new StreamReader(directory + fileName))
    {
        string line;
        while ((line = reader.ReadLine()) != null)
        {                    
            line = line.Replace(word, replacement);
            list.Add(line);
            Console.WriteLine(line);
        }
        reader.Close();
    }      
}

这是我目前为 StreamWriter 编写的代码:

and here is my code so far for the StreamWriter:

public void EditorialResponse(string fileName, string word, string replacement, string saveFileName)
{
    using (StreamWriter writer = new StreamWriter(directory + saveFileName, true))
    {
        {
            string input = directory + fileName;
            string line = input.Replace(word, replacement);
            writer.Write(line);                     
        }
        writer.Close();
    }
}

我可以添加什么来使 StreamWriter 打开文件、编辑单词并将其写入新文件或可能使用 StreamReader 方法在 StreamWriter 中进行这些更改?谢谢

what can I add to make the StreamWriter open a file, edit a word and write it to a new file or possibly use the StreamReader method to make these changes in StreamWriter? Thank you