Agfdhyk

I want to replace the second part of the string line of my .txt file. My .txt is:

admin|admin

ruiliberal|123456789

And I want to replace it like this for example:

admin|12345

ruiliberal|123456789

My code is:

string dirConta = Environment.CurrentDirectory + "/Bd/contas.txt";



private void buttonGravaPass_Click(object sender, EventArgs e)

{

    string lines = File.ReadLines(dirConta).ToArray();



    for (int i = 0; i < File.ReadAllLines(dirConta).Count(); i++)

    {



        string parts = lines[i].Split(new char { '|' });

        if (parts[0] == Users.user)

        {

            lines[i] = lines[i].Remove(lines[i].Length - 5);

            lines[i] = lines[i] + "12345";

        }

        File.WriteAllText(dirConta, lines[i]);

    }

}

This doesn´t work, it deletes the last line.

There are a few issues with your code.

First problem is: never store passwords in plain text. This is a horrible idea. If this is a production system, stop what you are doing and start from the ground up because this is bad. If this is just an exercise in learning and is not for any real future use then continue on...

Second, you are calling File.ReadLines() and File.ReadAllLines(), you dont need both. Just use File.ReadLines() as it returns an IEnumerable and lets you work on the results as they come in instead of waiting for all to be returned (which is what File.ReadAllLines() does).

Next, you should make a method that actually does the modification for you so you can reuse it if needed:

private static IEnumerable<string> ModifyLines(IEnumerable<string> inputLines)

{

    foreach(var line in inputLines)

    {

        var split = line.Split('|');

        yield return $"{split[0]}|12345";

    }

}

This will iterate the input IEnumerable, and yield return a new string. There really isn't any reason to modify the split array, just take the string you need (the username) and use string interpolation to format it with your static password ("12345").

Then when all is said and done you need to use File.WriteAllLines() method to write the results to file, not File.WriteAllText(). One of the reasons your code does not work is because you write all text inside the loop. If you read the docs to see what the method actually does you will see why it would not work the way you are using it.

So all together it would be:

private void buttonGravaPass_Click(object sender, EventArgs e)

{

    var lines = ModifyLines(File.ReadLines(dirConta));

    File.WriteAllLines(dirConta, lines.ToArray());

}

Fiddle here

Here's my spin on it...

using System;

using System.Collections.Generic;

using System.IO;



namespace Q_53401300

{

    class Program

    {



        static string dirConta = "C:\temp2\ListOfPWD.txt";



        static void Main(string args)

        {

            buttonGravaPass_Click(null, null);



        }



        private static void buttonGravaPass_Click(object sender, EventArgs e)

        {

            List<string> newLinesToWrite = new List<string>();

            using (System.IO.StreamReader sr = new StreamReader(dirConta))

            {

                string currentLine = string.Empty;

                while ((currentLine = sr.ReadLine()) != null)

                {

                    string parts = currentLine.Split(new char { '|' });

                    //if (parts[0] == Users.user)

                    //{

                    parts[0] = parts[0].Remove(parts[0].Length - 5);

                    parts[1] = parts[1] + "12345";

                    newLinesToWrite.Add($"{parts[0]}|{parts[1]}");

                    //}

                }

            }

            System.IO.File.WriteAllLines(dirConta, newLinesToWrite);

        }

    }

}

Just in case you want to use your code here is the tested working version just change the lines in your code related to the ones below:

string lines = File.ReadLines(dirConta).ToArray();



        for (int i = 0; i < lines.Length; i++)

        {



            string parts = lines[i].Split(new char { '|' });

            if (parts[0] == Users.user)

            {

                lines[i] = lines[i].Remove(lines[i].Length - 5);

                lines[i] = lines[i] + "12345";

            }



        }

        File.WriteAllText(dirConta, string.Join("n",lines));

I hope this help as the other answers pointed what miss with the code.

So in my opinion there are a few things wrong with this code.

1.) Your for-loop:

for(int i = 0; i < lines.Count(); i++)

{ [...] }

you do not have to call ReadAllLines() again.
Or do:

foreach(string line in lines){[...]}

2.) Splitting into the parts:
Since you only have one splitting char you can call that like that:

string parts = lines[i].Split('|');

3.) Assigning the new string value:
Why not just do that:

lines[i] = $"{parts[0]}|12345";

4.) I would not suggest to write to the file in every loop. Just put File.WriteAllText(dirConta, lines[i]); outside your for-loop

5.) If you want to store data, I would strongly suggest to look into object-serialization. It makes alot of stuff easier.
See: Json Serialization in C#

There's a few problems with your approach. First, you should try to avoid + when concatenating strings. Use $"" or string.Format instead. Second, when event-programming, it's best to write another method that the event method calls so that you can avoid blocking the UI thread with unnecessary work (like writing to a file for example). Looking at the documentation for System.IO, it's possible to iterate over the lines of text using File.ReadLines so I did that instead of reading the file twice to get the number of lines. Also, instead of using Remove and +, just use Replace; it's much easier. Finally, you need to make sure you write all the text you have. Right now, you're only writing the first line.

string dirConta = $"{Environment.CurrentDirectory}/Bd/contas.txt";



private async Task ModifyFileAsync()

{

    var output = new List<string>();

    using (var reader = new StreamReader(dirConta))

    {

        while ((var line = await reader.ReadLineAsync().ConfigureAwait(false)) != null)

        {

            var parts = line.Split('|');

            if (parts[0] == Users.user)

            {

                var newLine = line.Replace(parts[1], "12345");

                lines.Add(newLine);

            }

            else

            {

                lines.Add(line);

            }

        }

    }



    using (var writer = new StreamWriter(dirConta))

    {

        foreach (var line in lines)

        {

            await writer.WriteLineAsync(line).ConfigureAwait(false);

        }

    }

}



private async void buttonGravaPass_Click(object sender, EventArgs e)

{

    await ModifyFileAsync().ConfigureAwait(false);

}