Hex editing a file within C#?

Question

I'm looking at removing a large section of bytes from within a file and then inserting a new large section of bytes starting in the same place the original removed bytes did, all using C#. Does anyone know how to go about this? I can't see to find any help online.

Any help would be much appreciated!

Thanks.

What part of the process do you not understand how to do? Reading the file, editing the read file, or saving the edited file? The saving and loading part you should be able to find plenty of tutorials for — Scott Chamberlain
– Scott Chamberlain, Commented Apr 18, 2016 at 23:16
@ScottChamberlain I'm not sure how to do the hex editing part (removing the existing bytes, then adding the new ones). I've never done something like that in C# before. — MattFiler
– MattFiler, Commented Apr 18, 2016 at 23:36
When you say insert, do you mean to preserve the bytes in the destination file that are past the offset? Also how large is the data? If it extends beyond what can reasonably be held in memory there will need to be additional code to hold a buffer while transferring the bytes. — Andrew Tavera
– Andrew Tavera, Commented Apr 19, 2016 at 5:31

TLJ · Accepted Answer · 2016-04-19 01:47:12Z

1

This should get you started.

Steps are as follow:

Find a position you want to edit.
Prepare your new data
Write

.

using System;
using System.Text;
using System.IO;

namespace Test
{
    class Program
    {
        static void Main(string[] args)
        {

            using (BinaryWriter writer = new BinaryWriter(File.Open("TextFile1.txt", FileMode.Open, FileAccess.ReadWrite)))
            {
                int offset = 1; //position you want to start editing
                byte[] new_data = new byte[] { 0x68, 0x69 }; //new data
                writer.Seek(offset, SeekOrigin.Begin); //move your cursor to the position
                writer.Write(new_data);//write it      
            }
        }
    }
}

edited Apr 19, 2016 at 1:47

answered Apr 19, 2016 at 1:40

TLJ

4,9854 gold badges34 silver badges47 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

MattFiler Over a year ago

Thanks for the response, would it be possible to use another BinaryWriter to fill the new_data variable with content from another file?

TLJ Over a year ago

you can populate your buffer using BinaryReader and follow the same flow. (do it by chunk if needed) msdn.microsoft.com/en-us/library/…

Collectives™ on Stack Overflow

Hex editing a file within C#?

1 Answer 1

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related