Develop Reference

Why do I get a different value after turning an integer into ASCII and then back to an integer?

Why, when I turn INT value to bytes and to ASCII and back, I get another value?
Example:
var asciiStr = new string(Encoding.ASCII.GetChars(BitConverter.GetBytes(2000)));
var intVal = BitConverter.ToInt32(Encoding.ASCII.GetBytes(asciiStr), 0);
Console.WriteLine(intVal);
// Result: 1855

ASCII is only 7-bit - code points above 127 are unsupported. Unsupported characters are converted to ? per the docs on Encoding.ASCII:
The ASCIIEncoding object that is returned by this property might not have the appropriate behavior for your app. It uses replacement fallback to replace each string that it cannot encode and each byte that it cannot decode with a question mark ("?") character.
So 2000 decimal = D0 07 00 00 hexadecimal (little endian) = [unsupported character] [BEL character] [NUL character] [NUL character] = ? [BEL character] [NUL character] [NUL character] = 3F 07 00 00 hexadecimal (little endian) = 1855 decimal.

TL;DR: Everything's fine. But you're a victim of character replacement.
We start with 2000. Let's acknowledge, first, that this number can be represented in hexadecimal as 0x000007d0.
BitConverter.GetBytes
BitConverter.GetBytes(2000) is an array of 4 bytes, Because 2000 is a 32-bit integer literal. So the 32-bit integer representation, in little endian (least significant byte first), is given by the following byte sequence { 0xd0, 0x07, 0x00, 0x00 }. In decimal, those same bytes are { 208, 7, 0, 0 }
Encoding.ASCII.GetChars
Uh oh! Problem. Here's where things likely took an unexpected turn for you.
You're asking the system to interpret those bytes as ASCII-encoded data. The problem is that ASCII uses codes from 0-127. The byte with value 208 (0xd0) doesn't correspond to any character encodable by ASCII. So what actually happens?
When decoding ASCII, if it encounters a byte that is out of the range 0-127 then it decodes that byte to a replacement character and moves to the next byte. This replacement character is a question mark ?. So the 4 chars you get back from Encoding.ASCII.GetChars are ?, BEL (bell), NUL (null) and NUL (null).
BEL is the ASCII name of the character with code 7, which traditionally elicits a beep when presented on a capable terminal. NUL (code 0) is a null character traditionally used for representing the end of a string.
new string
Now you create a string from that array of chars. In C# a string is perfectly capable of representing a NUL character within the body of a string, so your string will have two NUL chars in it. They can be represented in C# string literals with "\0", in case you want to try that yourself. A C# string literal that represents the string you have would be "?\a\0\0" Did you know that the BEL character can be represented with the escape sequence \a? Many people don't.
Encoding.ASCII.GetBytes
Now you begin the reverse journey. Your string is comprised entirely of characters in the ASCII range. The encoding of a question mark is code 63 (0x3F). And the BEL is 7, and the NUL is 0. so the bytes are { 0x3f, 0x07, 0x00, 0x00 }. Surprised? Well, you're encoding a question mark now where before you provided a 208 (0xd0) byte that was not representable with ASCII encoding.
BitConverter.ToInt32
Converting these four bytes back to a 32-bit integer gives the integer 0x0000073f, which, in decimal, is 1855.

String encoding (ASCII, UTF8, SHIFT_JIS, etc.) is designed to pigeonhole human language into a binary (byte) form. It isn't designed to store arbitrary binary data, such as the binary form of an integer.
While your binary data will be interpreted as a string, some of the information will be lost, meaning that storing binary data in this way will fail in the general case. You can see the point where this fails using the following code:
for (int i = 0; i < 255; ++i)
{
var byteData = new byte[] { (byte)i };
var stringData = System.Text.Encoding.ASCII.GetString(byteData);
var encodedAsBytes = System.Text.Encoding.ASCII.GetBytes(stringData);
Console.WriteLine("{0} vs {1}", i, (int)encodedAsBytes[0]);
}
Try it online
As you can see it starts off well because all of the character codes correspond to ASCII characters, but once we get up in the numbers (i.e. 128 and beyond), we start to require a more than 7 bits to store the binary value. At this point it ceases to be decoded correctly, and we start seeing 63 come back instead of the input value.
Ultimately you will have this problem encoding binary data using any string encoding. You need to choose an encoding method specifically meant for storing binary data as a string.
Two popular methods are:
Hexadecimal
Base64 using ToBase64String and FromBase64String
Hexadecimal example (using the hex methods here):
int initialValue = 2000;
Console.WriteLine(initialValue);
// Convert from int to bytes and then to hex
byte[] bytesValue = BitConverter.GetBytes(initialValue);
string stringValue = ByteArrayToString(bytesValue);
Console.WriteLine("As hex: {0}", stringValue); // outputs D0070000
// Convert form hex to bytes and then to int
byte[] decodedBytesValue = StringToByteArray(stringValue);
int intValue = BitConverter.ToInt32(decodedBytesValue, 0);
Console.WriteLine(intValue);
Try it online
Base64 example:
int initialValue = 2000;
Console.WriteLine(initialValue);
// Convert from int to bytes and then to base64
byte[] bytesValue = BitConverter.GetBytes(initialValue);
string stringValue = Convert.ToBase64String(bytesValue);
Console.WriteLine("As base64: {0}", stringValue); // outputs 0AcAAA==
// Convert form base64 to bytes and then to int
byte[] decodedBytesValue = Convert.FromBase64String(stringValue);
int intValue = BitConverter.ToInt32(decodedBytesValue, 0);
Console.WriteLine(intValue);
Try it online
P.S. If you simply wanted to convert your integer to a string (e.g. "2000") then you can simply use .ToString():
int initialValue = 2000;
string stringValue = initialValue.ToString();

How to convert From Hex To Dump in C#

I convert my Hex to dump to get special character like symbol but when I try to convert my "0x18" i "\u0018" this value. Can anyone give me solution regarding this matter.
Here is my code:
public static string FromHexDump(string sText)
{
Int32 lIdx;
string prValue ="" ;
for (lIdx = 1; lIdx < sText.Length; lIdx += 2)
{
string prString = "0x" + Mid(sText, lIdx, 2);
string prUniCode = Convert.ToChar(Convert.ToInt64(prString,16)).ToString();
prValue = prValue + prUniCode;
}
return prValue;
}
I used VB language. I have a database that already encrypted text to my password and the value is BAA37D40186D like this so I loop it by step 2 and it will like this 0xBA,0xA3,0x7D,0x40,0x18,0x6D and the VB result getting like this º£}#m

You can use this code:
var myHex = '\x0633';
var formattedString += string.Format(#"\x{0:x4}", (int)myHex);
Or you can use this code from MSDN (https://learn.microsoft.com/en-us/dotnet/csharp/programming-guide/types/how-to-convert-between-hexadecimal-strings-and-numeric-types):
string hexValues = "48 65 6C 6C 6F 20 57 6F 72 6C 64 21";
string[] hexValuesSplit = hexValues.Split(' ');
foreach (string hex in hexValuesSplit)
{
// Convert the number expressed in base-16 to an integer.
int value = Convert.ToInt32(hex, 16);
// Get the character corresponding to the integral value.
string stringValue = Char.ConvertFromUtf32(value);
char charValue = (char)value;
Console.WriteLine("hexadecimal value = {0}, int value = {1}, char value = {2} or {3}",
hex, value, stringValue, charValue);
}

The question is unclear - what is the database column's type? Does it contain 6 bytes, or 12 characters with the hex encoding of the bytes? In any case, this has nothing to do with special characters or encodings.
First, 0x18 is the byte value of the Cancel Character in the Latin 1 codepage, not the pound sign. That's 0xA3. It seems that the byte values in the question are just the Latin 1 bytes for the string in hex.
.NET strings are Unicode (UTF16LE specifically). There's no UTF8 string or Latin1 string. Encodings and codepages apply when converting bytes to strings or vice versa. This is done using the Encoding class and eg Encoding.GetBytes
In this case, this code will convert the byte to the expected string form, including the unprintable character :
new byte[] {0xBA,0xA3,0x7D,0x40,0x18,0x6D};
var latinEncoding=Encoding.GetEncoding(1252);
var result=latinEncoding.GetString(dbBytes);
The result is :
º£}#m
With the Cancel character between # and m.
If the database column contains the byte values as strings :
it takes double the required space and
the hex values have to be converted back to bytes before converting to strings
The x format is used to convert numbers or bytes to their hex form and vice versa. For each byte value, ToString("x") returns the hex string.
The hex string can be produced from the original buffer with :
var dbBytes=new byte[] {0xBA,0xA3,0x7D,0x40,0x18,0x6D};
var hexString=String.Join("",dbBytes.Select(c=>c.ToString("x")));
There are many questions that show how to parse a byte string into a byte array. I'll just steal Jared Parson's LINQ answer :
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();
}
With that, we can parse the hex string into a byte array and convert it to the original string :
var bytes=StringToByteArray(hexString);
var latinEncoding=Encoding.GetEncoding(1252);
var result=latinEncoding.GetString(bytes);

First of all u don't need dump but Unicode, I would recomend to read about unicode/encoding etc and why this is a problem with strings.
PS: solution : StackOverflow

C# Convert Hex String Array to Byte Array

I have a String[] of hex values "10" "0F" "3E" "42" stored.
I found this method to convert to a Byte[]
public static byte[] ToByteArray(String HexString)
{
int NumberChars = HexString.Length;
byte[] bytes = new byte[NumberChars / 2];
for (int i = 0; i < NumberChars; i += 2)
{
bytes[i / 2] = Convert.ToByte(HexString.Substring(i, 2), 16);
}
return bytes;
}
However this converts the values to the hex equivalent. But the values are already in the hex equivalent!
For example this makes "10" "0F" "3E" "42" into "16" "15" "62" "66".
I want it to directly copy the values as they are already the correct hex value.
Edit:
Basically...
I want a byte array with the literal characters in the String[] So say the second value in String[] is 0F. I want the first byte in Byte[] to be 0F and not 16
Any ideas?
Edit2
Let me clarify. I don't want to convert my String[] values into Hexadecimal, as they are already Hexadecimal. I want to directly copy them to a Byte[]
The problem is my string of values "10" "0F" "3E" 42" already has the hexadecimal value I want. I want the byte array to contain those exact values and not convert them, they are already hexadecimal form.

You have to convert (or parse) string in order to get byte since string and byte are different types:
// 10 == 10d
byte b = Convert.ToByte("10"); // if "10" is a decimal representation
// 16 == 0x10
byte b = Convert.ToByte("10", 16); // if "10" is a hexadecimal representation
If you want to process an array, you can try a simple Linq:
using System.Linq;
...
string[] hexValues = new string[] {
"10", "0F", "3E", "42"};
byte[] result = hexValues
.Select(value => Convert.ToByte(value, 16))
.ToArray();
If you want to print out result as hexadecimal, use formatting ("X2" format string - at least 2 hexadecimal digits, use captital letters):
// 10, 0F, 3E, 42
Console.Write(string.Join(", ", result.Select(b => b.ToString("X2"))));
Compare with same array but in a different format ("d2" - at least 2 decimal digits)
// 16, 15, 62, 66
Console.Write(string.Join(", ", result.Select(b => b.ToString("d2"))));
If no format provided, .Net uses default one and represents byte in decimal:
// 16, 15, 62, 66
Console.Write(string.Join(", ", result));

You're really confusing representation and numbers here.
A string like "0F" can be seen as a representation of a number in base 16, that is, in decimal representation, 16.
Which is the exact same thing as representing 16 as F or 0F or XVI or
IIIIIIIIIIIIIIII or whatever other representation you choose.
The string "0F" actually looks in memory like this
Hexadecimal representation:
0x30 0x46 0x00
Decimal representation:
48 70 0
Binary representation:
0b00110000 0b01000110 0b00000000

Byte is simply a data type which is infact a subset of an integer.
Byte takes interger values ranging from -2^7(-128) to 2^7-1$(127)
Calling Convert.ToByte(string, 16) simply converts your string to an equivalent hex value and then to an equivalent value in byte.
Note the byte data type is always an integer data but used in place of an integer just to save space in memory. As referenced above the byte datatype takes values from -128 to 127 thereby saving you more space in memory than the integer data type would.
Please Note that you are likely to run into an error if the hexadecimal value you wish to convert to byte is less than -128 or greater than 127
The link below shows an instance of this error when I try converting a string whose value when converted to hexadecimal is greater than 127.
Error when converting to Byte
You get an error whenever you do this.
I hope my answer and Dmitry Bychenko's sheds more light into your problem.
Please feel free to comment if it doesnt.

Convert from Hexadecimal to Text

With respect to this tool, I need to convert hexadecimal data, irrespective of their combination to equivalent text. For example:
"HelloWorld" = 48656c6c6f576f726c64;
The solution needs to take into account that hexadecimal can be grouped in different lengths:
48656c6c 6f576f72 6c64
or
48 65 6c 6c 6f 57 6f 72 6c 64
All of the hexadecimal values supplied above read as HelloWorld when converted to text.

First, I would like to point out that this question has been asked many times on the web (here is one example). However, I am going to break this down step by step for you to hopefully teach you how to not only utilize your resources available on the web, but also how to solve your problem.
Overview: Converting from hexadecimal data to text that is able to be read by human beings is a straight-forward process in modern development languages; you clean the data (ensuring no illegal characters remain), then you convert down to the byte level so that you can work with the raw data. Finally, you'll convert that raw data into readable text utilizing a method that has already been created by Microsoft.
Important: Remember, for the conversion to work, you have to ensure you're converting in the same format that you started with:
ASCII -> ASCII: Works Great!
ASCII -> UTF7: Not so much...
Removing Illegal Characters: One of the first things you'll need to do is ensure the hexadecimal value that you're supplying doesn't contain any illegal characters. The simplest way to do this is to create an array of acceptable characters and then remove anything but these in a loop:
private string GetCleanHex(string hex) {
string legalCharacters = "0123456789ABCDEF";
string result = hex.ToUpper();
foreach (char c in result) {
if (!legalCharacters.Contains(c))
result = result.Replace(c.ToString(), string.Empty);
}
}
Getting The Byte Array: Once you've cleaned out all illegal characters, you can now convert your hexadecimal string into a byte array. This is required to convert from hexadecimal to ASCII. This step was provided by the linked post above:
private byte[] GetBytesFromHex(string hex) {
byte[] bytes = new byte[result.Length / 2];
for (int i = 0; i < bytes.Length; i++)
bytes[i] = Convert.ToByte(result.Substring(i * 2, 2), 16);
}
Converting To Text: Now that you've cleaned your data, and converted it to a byte[], you can now convert that byte data into ASCII. This can be done using a method available in Encoding.ASCII called GetString:
string text = Encoding.ASCII.GetString(bytes);
The Final Result: Plug all of this into your application and you'll have successfully converted hexadecimal data into clean, readable text:
string hex = GetCleanHex("506c 65 61736520 72 656164 20686f77 2074 6f 2061 73 6b 2e");
byte[] bytes = GetBytesFromHex(hex);
string text = Encoding.ASCII.GetString(bytes);
Console.WriteLine(text);
Console.ReadKey();
The code above will print the following text to the console:
Please read how to ask.

convert Hex UTF-8 bytes to Hex code point

how can i convert
Hex UTF-8 bytes -E0 A4 A4 to hex code point - 0924
ref: http://www.ltg.ed.ac.uk/~richard/utf-8.cgi?input=e0+a4+a4&mode=bytes
I need this because when i read Unicode data in c# it is taking it as single byte sequence and displaying 3 characters instead of 1,but i need 3 byte sequence(read 3 bytes and display single character),I tried many solutions but didn't get the result.
If I can display or store a 3-byte sequence utf-8 character then I don't need conversion.
senario is like this:
string str=getivrresult();
in str I have a word with each character as 3 byte utf-8 sequence.
Edited:
string str="त";
//i want it as "त" in str.
Character त
Character name DEVANAGARI LETTER TA
Hex code point 0924
Decimal code point 2340
Hex UTF-8 bytes E0 A4 A4
Octal UTF-8 bytes 340 244 244
UTF-8 bytes as Latin-1 characters bytes à ¤ ¤
Thank You.

Use the GetString methdod in the Encoding class:
byte[] data = { 0xE0, 0xA4, 0xA4 };
string str = Encoding.UTF8.GetString(data);
The string now contains one character with the character code 0x924.

//utf-8 Single Byte Sequence input
string str = "त";
int i = 0;
byte[] data=new byte[3];
foreach (char c in str)
{
string tmpstr = String.Format("{0:x2}", (int)c);
data[i] = Convert.ToByte(int.Parse(tmpstr, System.Globalization.NumberStyles.HexNumber));
i++;
}
//utf-8 3-Byte Sequence Output now stp contains "त".
string stp = Encoding.UTF8.GetString(data);