Replacing text in text file won't change in the folder

Question

Been using this code to change the index of 1 to 50001, 50002 ect. But it doesn't seem to save in the text file. Is there a way to say file.Save? or am I doing something silly.

Here is my code

  int count = 50000;
        string line;

        //string str = File.ReadAllText();
        System.IO.StreamReader file =
        new System.IO.StreamReader(@"C:\Documents\new\example\example.txt");
        while ((line = file.ReadLine()) != null)
        {
            line = line.Replace(":1}}", ":" + count + "}}");
            count++;
        }

You have to write it back to your file using a `StreamWriter`. — MakePeaceGreatAgain, Sep 23 '16 at 08:40
Possible duplicate of [simultaneous read-write a file in C#](http://stackoverflow.com/questions/3817477/simultaneous-read-write-a-file-in-c-sharp) — MakePeaceGreatAgain, Sep 23 '16 at 08:41

Dmitry Bychenko · Accepted Answer · 2016-09-23T08:56:15.240

1

You have to write the changed data back:

  string path = @"C:\Documents\new\example\example.txt";

  int count = 50000; 

  var target = File
    .ReadLines(path)
    .Select(line => line.Replace(":1}}", ":" + count++ + "}}")) 
    .ToList(); // materialization required if you want to write back to the same file

  // You can here inspect, debug etc., what you're going to write back, e.g.
  // Console.Write(string.Join(Environment.NewLine, target));

  File.WriteAllLines(path, target);

edited Sep 23 '16 at 08:56

answered Sep 23 '16 at 08:44

Dmitry Bychenko

180,369
20
160
215

That looks much more cleaner than my approach ;-) – Mat Sep 23 '16 at 08:52
Amazing thanks. Is there any way you could search a file for all text file by using this... I have tired foreach (string file in Directory.EnumerateFiles(path, "*.txt", SearchOption.AllDirectories)) { – Nicola Sep 23 '16 at 09:08
1

@Nicola: yes, I suggest *extracting a method* for this: `public static void ChangeMyFile(string path) {/* the code from the answer here */}` and then you can use `foreach (string file in Directory.EnumerateFiles(path, "*.txt", SearchOption.AllDirectories)) {ChangeMyFile(file);}` – Dmitry Bychenko Sep 23 '16 at 09:13

Mat · Answer 2 · 2016-09-23T08:51:06.480

 int count = 50000;

        //string str = File.ReadAllText();
        string fileName = @"C:\Documents\new\example\example.txt";
        List<string> lines = new List<string>();

        using (System.IO.StreamReader file =
                    new System.IO.StreamReader(fileName))
        {
            string line;
            while ((line = file.ReadLine()) != null)
            {
                line = line.Replace(":1}}", ":" + count + "}}");
                lines.Add(line);                    
                count++;
            }
        }

        using (StreamWriter sw = new StreamWriter(fileName,false))
        {
            foreach (string line in lines)
            {
                sw.WriteLine(line);
            }
        }

You should add `line` changed into `lines` collection, e.g. `lines.Add(line);` — Dmitry Bychenko, Sep 23 '16 at 08:47

Replacing text in text file won't change in the folder

2 Answers2