c# Write to hex file

Question

Just made a mod installer to modify hex of a game file but it doesn't seem to write it correctly this is the code I use to write it:

BinaryWriter BWriter = new BinaryWriter(File.OpenWrite(HexFile));


        for (int i = value; i < value2; i++)
        {
            BWriter.BaseStream.Position = i;
            BWriter.Write(NewHex);
        }

And this is the "NewHex" that it should write:

1A 00 00 00 04 0B 19 01 4F 02 00 00 0A 00 00 00 00 00 00 1B 66 03 00 00 00 00 00 00 16 53 00 00

But it doesn't do that, instead, it converts that hex string to binary and then writes it to the file resulting in something totally different AND it writes a bunch of gibberish to the beginning: before the hex string, in this case 2 lines made up out of 61 were place before that hex thus breaking the game

Does anyone know a solution to this?

Thanks

EDIT: Fixed the first issue, now writes correctly, this is the new code:

 private void button4_Click(object sender, EventArgs e)
    {
        int value = (int)new System.ComponentModel.Int32Converter().ConvertFromString(StartAddr);
        int value2 = (int)new System.ComponentModel.Int32Converter().ConvertFromString(StopAddr);


        //int StopInt = int.Parse(StopAddr);
        BinaryWriter BWriter = new BinaryWriter(File.OpenWrite(HexFile));


        for (int i = value; i < value2; i++)
        {
            BWriter.BaseStream.Position = i;
            BWriter.Write(StringToByteArray(NewHex));
        }

    }
    public static byte[] StringToByteArray(string hex)
    {
        return Enumerable.Range(0, hex.Length)
                         .Where(x => x % 2 == 0)
                         .Select(x => Convert.ToByte(hex.Substring(x, 2), 16))
                         .ToArray();
    }

I can see that it wrote the hex correctly now but there is still one issue, it writes this:

1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 1A 00 00 00 04 0B 19 01 4F 02 00 00 0A 00 00 00 00 00 00 1B 66 03 00 00 00 00 00 00 16 53 00 00

Instead of this:

1A000000040B19014F0200000A0000000000001B660300000000000016530000

Does anyone know a solution for this problem?

Answer 1

I think StringToByteArray is working properly. However I can see that you loop

for (int i = value; i < value2; i++)
{
    BWriter.BaseStream.Position = i;
    BWriter.Write(StringToByteArray(NewHex));
}

will gradually write 1A000000040B19014F0200000A0000000000001B660300000000000016530000 to stream starting at each of stream position from value to value2 . Are sure you need this loop?

Answer 2

In your code, the Write method is the String overloaded version, which means it convert the exact type you pass it (string) to binary. The BinaryWriter.Write(String) overload - it prefixes the string with a single-byte length, which is not what you want. Therefore you will not see the hex value as you want to see in the file.

BWriter.Write(Encoding.ASCII.GetBytes(NewHex));

This would help you as well. C#: Write values into Binary (.bin) file format