C# get user input(offset) & (write new value to offset)

jihye

13y3.5k.NET

Hello

After trying for hours and googling around i give up, also used the search here and couldn't find anything that i'm looking for.

I'm trying to make a windows form application where the "user" can enter a offset & new value to be written to the offset.

I've been trying to do it with Console.ReadLine(is there a better way?) and 2 textbox but it kept writing 0x00000000

Example1:

Textbox1>Offset: 0x00001234
Textbox2>Value: 9A05FF80
http://i.imgur.com/733ySBV.jpg

also how about this? instead of offset+value it would be find&replace.

Example2:

Textbox1>Find: whatever the user inputs (example: 6316707C6301947C6307B4E80100C07C)
Textbox2>Replace: whatever the user inputs as new(example: 1F011F3751F5FBA34719F514236FB1B3)

Best Regards

6 Replies

Know the answer? Post it — somebody with the same question will find it here.

Vulpes13y ago
Accepted answer
You'll probably be better trying to get it to work as a console application before converting to windows forms.

I've added code to my previous effort to get the offset and value from the user including some rudimentary error handling.

For now, I've stuck to 4 byte offsets and values as I'm not sure how a greater number of bytes should be distributed amongst the arrays:

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

class Program
{
static void Main()
{

string ofs;
int iOfs;

do
{
Console.Write("Enter 4 byte hex offset : ");
ofs = Console.ReadLine().Trim().ToUpper();
if (ofs.StartsWith("0X")) ofs = ofs.Substring(2);
}
while(ofs.Length != 8
|| !int.TryParse(ofs, NumberStyles.AllowHexSpecifier, null, out iOfs));

int[] offset = {Convert.ToInt32(ofs.Substring(0, 2), 16)};
int[] offset_2 = {Convert.ToInt32(ofs.Substring(2, 2), 16)};
int[] offset_3 = {Convert.ToInt32(ofs.Substring(4, 2), 16)};
int[] offset_4 = {Convert.ToInt32(ofs.Substring(6, 2), 16)};

string value;
int iValue;

do
{
Console.Write("Enter 4 byte hex value : ");
value = Console.ReadLine().ToUpper();
if (value.StartsWith("0X")) value = value.Substring(2);
}
while(value.Length != 8
|| !int.TryParse(value, NumberStyles.AllowHexSpecifier, null, out iValue));

byte[] data = {Convert.ToByte(value.Substring(0, 2), 16)};
byte[] data_2 = {Convert.ToByte(value.Substring(2, 2), 16)};
byte[] data_3 = {Convert.ToByte(value.Substring(4, 2), 16)};
byte[] data_4 = {Convert.ToByte(value.Substring(6, 2), 16)};

using (Stream s = File.OpenWrite("file.bin"))
{
using (BinaryWriter bw = new BinaryWriter(s, Encoding.ASCII))
{
for(int i = 0; i < offset.Length; i++)
{
bw.Seek(offset[i], SeekOrigin.Begin);
bw.Write(data[i]);
bw.Seek(offset_2[i], SeekOrigin.Begin);
bw.Write(data_2[i]);
bw.Seek(offset_3[i], SeekOrigin.Begin);
bw.Write(data_3[i]);
bw.Seek(offset_4[i], SeekOrigin.Begin);
bw.Write(data_4[i]);
}
}
}
}
}
jihye13y ago
Awesome, thanks for the help <3
Although i dislike the way the offset is being read
0x00010203 = 0x00000000-0x00000003
jihye13y ago
Thanks really appreciate your reply, but i already knew how to do that(different method though) and that's not what i'm kinda trying to do :)

I'd like to be able to use it with ReadLine(); -unless of course there is something better than ReadLine- on a textbox so it retrieves the offset the user writes and also adds the value entered by the user.

Like the function "find & replace" at an Hex Editor but instead of find it would be "go to" offset and replace.

I'm too afraid to post my C# code cause you gonna laugh so i'll post something in C++ again :)

This would be used with the C++ code above.
int offset;
cout << "Offset:";
cin >> offset;

int data;
cout << "Value:";
cin >> data;
Vulpes13y ago
Ah, writing to offsets within a binary file is a different matter :)

That C++ code would translate to this in C# and writes "Hero" starting at offset D2:

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

class Program
{
static void Main()
{
int[] offset = {0x000000D2};
int[] offset_2 = {0x000000D3};
int[] offset_3 = {0x000000D4};
int[] offset_4 = {0x000000D5};

byte[] data = {0x48};
byte[] data_2 = {0x65};
byte[] data_3 = {0x72};
byte[] data_4 = {0x6F};

using (Stream s = File.OpenWrite("file.bin"))
{
using (BinaryWriter bw = new BinaryWriter(s, Encoding.ASCII))
{
for(int i = 0; i < offset.Length; i++)
{
bw.Seek(offset[i], SeekOrigin.Begin);
bw.Write(data[i]);
bw.Seek(offset_2[i], SeekOrigin.Begin);
bw.Write(data_2[i]);
bw.Seek(offset_3[i], SeekOrigin.Begin);
bw.Write(data_3[i]);
bw.Seek(offset_4[i], SeekOrigin.Begin);
bw.Write(data_4[i]);
}
}
}
}
}
jihye13y ago
I'm trying to write it directly to files, whatever the user inputs as offset/new value. Hope you understand what i mean.

Like this code in C++, however this is in C++ and it's not with cout/cin and besides i gave up on C++ for now.

int main() {
ofstream f("FILE", ios::in | ios::out | ios::binary);
if (f.fail()) return -1;

int offset[] = {0x000000D2};
int offset_2[] = {0x000000D3};
int offset_3[] = {0x000000D4};
int offset_4[] = {0x000000D5};

char data[] = {0x48};
char data_2[] = {0x65};
char data_3[] = {0x72};
char data_4[] = {0x6F};

for (int i=0; i f.seekp(offset[i], ios::beg);
f.put(data[i]);
f.seekp(offset_2[i], ios::beg);
f.put(data_2[i]);
f.seekp(offset_3[i], ios::beg);
f.put(data_3[i]);
f.seekp(offset_4[i], ios::beg);
f.put(data_4[i]);

}

f.close();
return 0;
}
Vulpes13y ago
If those are supposed to be offsets into heap memory, then you can't write arbitrary values into them using C# which is a 'safe' language.

Why would you want to do this anyway as you're likely to corrupt the heap?