Develop Reference

How to read blob data from MySQL in c# [duplicate]

I have a byte[] array that is loaded from a file that I happen to known contains UTF-8.
In some debugging code, I need to convert it to a string. Is there a one-liner that will do this?
Under the covers it should be just an allocation and a memcopy, so even if it is not implemented, it should be possible.

string result = System.Text.Encoding.UTF8.GetString(byteArray);

There're at least four different ways doing this conversion.
Encoding's GetString, but you won't be able to get the original bytes back if those bytes have non-ASCII characters.
BitConverter.ToString The output is a "-" delimited string, but there's no .NET built-in method to convert the string back to byte array.
Convert.ToBase64String You can easily convert the output string back to byte array by using Convert.FromBase64String. Note: The output string could contain '+', '/' and '='. If you want to use the string in a URL, you need to explicitly encode it.
HttpServerUtility.UrlTokenEncodeYou can easily convert the output string back to byte array by using HttpServerUtility.UrlTokenDecode. The output string is already URL friendly! The downside is it needs System.Web assembly if your project is not a web project.
A full example:
byte[] bytes = { 130, 200, 234, 23 }; // A byte array contains non-ASCII (or non-readable) characters
string s1 = Encoding.UTF8.GetString(bytes); // ���
byte[] decBytes1 = Encoding.UTF8.GetBytes(s1); // decBytes1.Length == 10 !!
// decBytes1 not same as bytes
// Using UTF-8 or other Encoding object will get similar results
string s2 = BitConverter.ToString(bytes); // 82-C8-EA-17
String[] tempAry = s2.Split('-');
byte[] decBytes2 = new byte[tempAry.Length];
for (int i = 0; i < tempAry.Length; i++)
decBytes2[i] = Convert.ToByte(tempAry[i], 16);
// decBytes2 same as bytes
string s3 = Convert.ToBase64String(bytes); // gsjqFw==
byte[] decByte3 = Convert.FromBase64String(s3);
// decByte3 same as bytes
string s4 = HttpServerUtility.UrlTokenEncode(bytes); // gsjqFw2
byte[] decBytes4 = HttpServerUtility.UrlTokenDecode(s4);
// decBytes4 same as bytes

A general solution to convert from byte array to string when you don't know the encoding:
static string BytesToStringConverted(byte[] bytes)
{
using (var stream = new MemoryStream(bytes))
{
using (var streamReader = new StreamReader(stream))
{
return streamReader.ReadToEnd();
}
}
}

Definition:
public static string ConvertByteToString(this byte[] source)
{
return source != null ? System.Text.Encoding.UTF8.GetString(source) : null;
}
Using:
string result = input.ConvertByteToString();

Converting a byte[] to a string seems simple, but any kind of encoding is likely to mess up the output string. This little function just works without any unexpected results:
private string ToString(byte[] bytes)
{
string response = string.Empty;
foreach (byte b in bytes)
response += (Char)b;
return response;
}

I saw some answers at this post and it's possible to be considered completed base knowledge, because I have a several approaches in C# Programming to resolve the same problem. The only thing that is necessary to be considered is about a difference between pure UTF-8 and UTF-8 with a BOM.
Last week, at my job, I needed to develop one functionality that outputs CSV files with a BOM and other CSV files with pure UTF-8 (without a BOM). Each CSV file encoding type will be consumed by different non-standardized APIs. One API reads UTF-8 with a BOM and the other API reads without a BOM. I needed to research the references about this concept, reading the "What's the difference between UTF-8 and UTF-8 without BOM?" Stack Overflow question, and the Wikipedia article "Byte order mark" to build my approach.
Finally, my C# Programming for both UTF-8 encoding types (with BOM and pure) needed to be similar to this example below:
// For UTF-8 with BOM, equals shared by Zanoni (at top)
string result = System.Text.Encoding.UTF8.GetString(byteArray);
//for Pure UTF-8 (without B.O.M.)
string result = (new UTF8Encoding(false)).GetString(byteArray);

Using (byte)b.ToString("x2"), Outputs b4b5dfe475e58b67
public static class Ext {
public static string ToHexString(this byte[] hex)
{
if (hex == null) return null;
if (hex.Length == 0) return string.Empty;
var s = new StringBuilder();
foreach (byte b in hex) {
s.Append(b.ToString("x2"));
}
return s.ToString();
}
public static byte[] ToHexBytes(this string hex)
{
if (hex == null) return null;
if (hex.Length == 0) return new byte[0];
int l = hex.Length / 2;
var b = new byte[l];
for (int i = 0; i < l; ++i) {
b[i] = Convert.ToByte(hex.Substring(i * 2, 2), 16);
}
return b;
}
public static bool EqualsTo(this byte[] bytes, byte[] bytesToCompare)
{
if (bytes == null && bytesToCompare == null) return true; // ?
if (bytes == null || bytesToCompare == null) return false;
if (object.ReferenceEquals(bytes, bytesToCompare)) return true;
if (bytes.Length != bytesToCompare.Length) return false;
for (int i = 0; i < bytes.Length; ++i) {
if (bytes[i] != bytesToCompare[i]) return false;
}
return true;
}
}

There is also class UnicodeEncoding, quite simple in usage:
ByteConverter = new UnicodeEncoding();
string stringDataForEncoding = "My Secret Data!";
byte[] dataEncoded = ByteConverter.GetBytes(stringDataForEncoding);
Console.WriteLine("Data after decoding: {0}", ByteConverter.GetString(dataEncoded));

In addition to the selected answer, if you're using .NET 3.5 or .NET 3.5 CE, you have to specify the index of the first byte to decode, and the number of bytes to decode:
string result = System.Text.Encoding.UTF8.GetString(byteArray, 0, byteArray.Length);

Alternatively:
var byteStr = Convert.ToBase64String(bytes);

The BitConverter class can be used to convert a byte[] to string.
var convertedString = BitConverter.ToString(byteAttay);
Documentation of BitConverter class can be fount on MSDN.

To my knowledge none of the given answers guarantee correct behavior with null termination. Until someone shows me differently I wrote my own static class for handling this with the following methods:
// Mimics the functionality of strlen() in c/c++
// Needed because niether StringBuilder or Encoding.*.GetString() handle \0 well
static int StringLength(byte[] buffer, int startIndex = 0)
{
int strlen = 0;
while
(
(startIndex + strlen + 1) < buffer.Length // Make sure incrementing won't break any bounds
&& buffer[startIndex + strlen] != 0 // The typical null terimation check
)
{
++strlen;
}
return strlen;
}
// This is messy, but I haven't found a built-in way in c# that guarentees null termination
public static string ParseBytes(byte[] buffer, out int strlen, int startIndex = 0)
{
strlen = StringLength(buffer, startIndex);
byte[] c_str = new byte[strlen];
Array.Copy(buffer, startIndex, c_str, 0, strlen);
return Encoding.UTF8.GetString(c_str);
}
The reason for the startIndex was in the example I was working on specifically I needed to parse a byte[] as an array of null terminated strings. It can be safely ignored in the simple case

A LINQ one-liner for converting a byte array byteArrFilename read from a file to a pure ASCII C-style zero-terminated string would be this: Handy for reading things like file index tables in old archive formats.
String filename = new String(byteArrFilename.TakeWhile(x => x != 0)
.Select(x => x < 128 ? (Char)x : '?').ToArray());
I use '?' as the default character for anything not pure ASCII here, but that can be changed, of course. If you want to be sure you can detect it, just use '\0' instead, since the TakeWhile at the start ensures that a string built this way cannot possibly contain '\0' values from the input source.

Try this console application:
static void Main(string[] args)
{
//Encoding _UTF8 = Encoding.UTF8;
string[] _mainString = { "Hello, World!" };
Console.WriteLine("Main String: " + _mainString);
// Convert a string to UTF-8 bytes.
byte[] _utf8Bytes = Encoding.UTF8.GetBytes(_mainString[0]);
// Convert UTF-8 bytes to a string.
string _stringuUnicode = Encoding.UTF8.GetString(_utf8Bytes);
Console.WriteLine("String Unicode: " + _stringuUnicode);
}

Here is a result where you didn’t have to bother with encoding. I used it in my network class and send binary objects as string with it.
public static byte[] String2ByteArray(string str)
{
char[] chars = str.ToArray();
byte[] bytes = new byte[chars.Length * 2];
for (int i = 0; i < chars.Length; i++)
Array.Copy(BitConverter.GetBytes(chars[i]), 0, bytes, i * 2, 2);
return bytes;
}
public static string ByteArray2String(byte[] bytes)
{
char[] chars = new char[bytes.Length / 2];
for (int i = 0; i < chars.Length; i++)
chars[i] = BitConverter.ToChar(bytes, i * 2);
return new string(chars);
}

string result = ASCIIEncoding.UTF8.GetString(byteArray);

How to convert a large hexadecimal string to a byte array?

Hi I am in need of using file handling,for that i used a method for converting a hexadecimal string into a byte array.
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();
}
My problem is ,when i give a small hexadecimal string as a parameter to this function it will produce the right output,but when i used a large hexadecimal string as a parameter output is not that expected.
for your clear understanding -
I used a hexadecimal string which is being converted from a byte array of value [26246026],
when i convert that hex string into a byte array it should return a byte value as [26246026] - but its returning only the partial bytes ie.[262144].
i cant get the exact byte value from the hex string,how can i get that?
Please someone help me to get the expected output.
My input string for that method contains this hexadecimel string which is a 25mb size file-it should return a byte value of [26246026]---but its returning only the byte value of [262144].
when am using small hex string (min size file) its working fine,but when i work on big files i cant get the original file byte. please suggest me what to do.
my input parameter string content is as follow as asked in comment.
Its totally 524288 characters in length..
looks like this.
3026b2758e66cf11a6d900aa0062ce6c301600000000000008000000010240a4d0d207e3d21197f000a0c95ea850cc0000000000000004001c00530066004f0072006900670069006e0061006c00460050005300000003000400b49204001c0057004d004600530044004b00560065007200730069006f006e00000000001e00310031002e0030002e0036003000300031002e00370030003000300000001a0057004d004600530044004b004e006500650064006500640000000000160030002e0030002e0030002e00300030003000300000000c0049007300560042005200000002000400000000003326b2758e66cf11a6..........................................................................................................................................
d900aa0062ce6c54010000000000001e0000003a00da000000570dcb8b495848cea4609eca906bc24db442394f0ddac5eb0604fb99820bcc30ff0f1736eefd74cd4317a21a369e208c580dbb02f90e888f0a35901e08439ec6087c61d241bc3c476c24d311291a678596a98792a9000b68adf213906e0f00097c8d989e517ee532fcd6cb70e520ec9dd4fad8a1a37668bbd678bea11c1fcf2d187c4c4c6c09c3c2c53d3e64016cfebc34eace85d45a4c08cd78d05d3934e05b72ec194304848165a8c1a585c78423

/// <summary>
/// Parses a continuous hex stream from a string.
/// </summary>
public static byte[] ParseHexBytes(this string s)
{
if (s == null)
throw new ArgumentNullException("s");
if (s.Length == 0)
return new byte[0];
if (s.Length % 2 != 0)
throw new ArgumentException("Source length error", "s");
int length = s.Length >> 1;
byte[] result = new byte[length];
for (int i = 0; i < length; i++)
{
result[i] = Byte.Parse(s.Substring(i * 2, 2), NumberStyles.HexNumber);
}
return result;
}

C# Character from Unicode

I have a unicode character from the FontAwesome cheat sheet:
#xf042;
How do I put that character into c# ?
string s = "????";
I have tried entering it is as and using a .

If you just want a lighter version of what Darin posted to convert the hex value to a string containing the unicode position from the private area of the FontAwesome font, you can use this >>
private static string UnicodeToChar( string hex ) {
int code=int.Parse( hex, System.Globalization.NumberStyles.HexNumber );
string unicodeString=char.ConvertFromUtf32( code );
return unicodeString;
}
Just call it as follows >>
string s = UnicodeToChar( "f042" );
Alternatively, you can simply use the C# class with all the icons and loader pre-written here >> FontAwesome For WinForms CSharp

Assuming the hex input represents UTF8 encoded string you could have a function that will convert a HEX string:
public static string ConvertHexToString(string hex)
{
int numberChars = hex.Length;
byte[] bytes = new byte[numberChars / 2];
for (int i = 0; i < numberChars; i += 2)
{
bytes[i / 2] = Convert.ToByte(hex.Substring(i, 2), 16);
}
return Encoding.UTF8.GetString(bytes);
}
and then filter out the unnecessary characters from your input before feeding it to this function:
string input = "#xf042;";
string s = input.Replace("#x", string.Empty).Replace(";", string.Empty);
string result = ConvertHexToString(s);
Obviously you will need to adjust the correct encoding based on the input, because the hex simply represents a byte array and in order to decode this byte array back to a string you're gonna need to know the encoding.

how to recode back? BitConverter

byte[] test = Form1.StrToByteArray("simpletext");
string encoded_text = BitConverter.ToString(test).Replace("-", "").ToLowerInvariant();
textBox1.Text = encoded_text;//73696d706c6574657874
as from this line "73696d706c6574657874" to get back "simpletext" ??
//StrToByteArray()
public static byte[] StrToByteArray(string str)
{
System.Text.ASCIIEncoding encoding = new System.Text.ASCIIEncoding();
return encoding.GetBytes(str);
}

Do you absolutely have to use hex to start with? One slightly more efficient (and reversible with framework methods) option would be to use base 64:
string base64 = Convert.ToBase64String(test);
byte[] originalBytes = Convert.FromBase64String(base64);
string text = Encoding.ASCII.GetString(originalBytes);
I personally wouldn't suggest using ASCII as your encoding, however - UTF-8 will work the same way for ASCII characters, but allow all of Unicode to be encoded.
If you do have to use hex, you'll need a method to parse hex - I have an example here.

var input = "73696d706c6574657874";
var bytes = Enumerable
.Range(0, input.Length)
.Where(x => 0 == x % 2)
.Select(x => Convert.ToByte(input.Substring(x, 2), 16))
.ToArray();
Console.WriteLine(Encoding.ASCII.GetString(bytes));

should have done so
public static byte[] StrToByteArray(string str)
{
System.Text.UTF8Encoding encoding = new System.Text.UTF8Encoding();
return encoding.GetBytes(str);
}
//here im replace ASCIIEncoding to UTF8Encoding how said me Darin Dimitrov. respect man!!! very thx!!!!
and now i have result equal A-ґР^E—‹

How to convert UTF-8 byte[] to string

I have a byte[] array that is loaded from a file that I happen to known contains UTF-8.
In some debugging code, I need to convert it to a string. Is there a one-liner that will do this?
Under the covers it should be just an allocation and a memcopy, so even if it is not implemented, it should be possible.

string result = System.Text.Encoding.UTF8.GetString(byteArray);

There're at least four different ways doing this conversion.
Encoding's GetString, but you won't be able to get the original bytes back if those bytes have non-ASCII characters.
BitConverter.ToString The output is a "-" delimited string, but there's no .NET built-in method to convert the string back to byte array.
Convert.ToBase64String You can easily convert the output string back to byte array by using Convert.FromBase64String. Note: The output string could contain '+', '/' and '='. If you want to use the string in a URL, you need to explicitly encode it.
HttpServerUtility.UrlTokenEncodeYou can easily convert the output string back to byte array by using HttpServerUtility.UrlTokenDecode. The output string is already URL friendly! The downside is it needs System.Web assembly if your project is not a web project.
A full example:
byte[] bytes = { 130, 200, 234, 23 }; // A byte array contains non-ASCII (or non-readable) characters
string s1 = Encoding.UTF8.GetString(bytes); // ���
byte[] decBytes1 = Encoding.UTF8.GetBytes(s1); // decBytes1.Length == 10 !!
// decBytes1 not same as bytes
// Using UTF-8 or other Encoding object will get similar results
string s2 = BitConverter.ToString(bytes); // 82-C8-EA-17
String[] tempAry = s2.Split('-');
byte[] decBytes2 = new byte[tempAry.Length];
for (int i = 0; i < tempAry.Length; i++)
decBytes2[i] = Convert.ToByte(tempAry[i], 16);
// decBytes2 same as bytes
string s3 = Convert.ToBase64String(bytes); // gsjqFw==
byte[] decByte3 = Convert.FromBase64String(s3);
// decByte3 same as bytes
string s4 = HttpServerUtility.UrlTokenEncode(bytes); // gsjqFw2
byte[] decBytes4 = HttpServerUtility.UrlTokenDecode(s4);
// decBytes4 same as bytes

A general solution to convert from byte array to string when you don't know the encoding:
static string BytesToStringConverted(byte[] bytes)
{
using (var stream = new MemoryStream(bytes))
{
using (var streamReader = new StreamReader(stream))
{
return streamReader.ReadToEnd();
}
}
}

Definition:
public static string ConvertByteToString(this byte[] source)
{
return source != null ? System.Text.Encoding.UTF8.GetString(source) : null;
}
Using:
string result = input.ConvertByteToString();

Converting a byte[] to a string seems simple, but any kind of encoding is likely to mess up the output string. This little function just works without any unexpected results:
private string ToString(byte[] bytes)
{
string response = string.Empty;
foreach (byte b in bytes)
response += (Char)b;
return response;
}

I saw some answers at this post and it's possible to be considered completed base knowledge, because I have a several approaches in C# Programming to resolve the same problem. The only thing that is necessary to be considered is about a difference between pure UTF-8 and UTF-8 with a BOM.
Last week, at my job, I needed to develop one functionality that outputs CSV files with a BOM and other CSV files with pure UTF-8 (without a BOM). Each CSV file encoding type will be consumed by different non-standardized APIs. One API reads UTF-8 with a BOM and the other API reads without a BOM. I needed to research the references about this concept, reading the "What's the difference between UTF-8 and UTF-8 without BOM?" Stack Overflow question, and the Wikipedia article "Byte order mark" to build my approach.
Finally, my C# Programming for both UTF-8 encoding types (with BOM and pure) needed to be similar to this example below:
// For UTF-8 with BOM, equals shared by Zanoni (at top)
string result = System.Text.Encoding.UTF8.GetString(byteArray);
//for Pure UTF-8 (without B.O.M.)
string result = (new UTF8Encoding(false)).GetString(byteArray);

Using (byte)b.ToString("x2"), Outputs b4b5dfe475e58b67
public static class Ext {
public static string ToHexString(this byte[] hex)
{
if (hex == null) return null;
if (hex.Length == 0) return string.Empty;
var s = new StringBuilder();
foreach (byte b in hex) {
s.Append(b.ToString("x2"));
}
return s.ToString();
}
public static byte[] ToHexBytes(this string hex)
{
if (hex == null) return null;
if (hex.Length == 0) return new byte[0];
int l = hex.Length / 2;
var b = new byte[l];
for (int i = 0; i < l; ++i) {
b[i] = Convert.ToByte(hex.Substring(i * 2, 2), 16);
}
return b;
}
public static bool EqualsTo(this byte[] bytes, byte[] bytesToCompare)
{
if (bytes == null && bytesToCompare == null) return true; // ?
if (bytes == null || bytesToCompare == null) return false;
if (object.ReferenceEquals(bytes, bytesToCompare)) return true;
if (bytes.Length != bytesToCompare.Length) return false;
for (int i = 0; i < bytes.Length; ++i) {
if (bytes[i] != bytesToCompare[i]) return false;
}
return true;
}
}

There is also class UnicodeEncoding, quite simple in usage:
ByteConverter = new UnicodeEncoding();
string stringDataForEncoding = "My Secret Data!";
byte[] dataEncoded = ByteConverter.GetBytes(stringDataForEncoding);
Console.WriteLine("Data after decoding: {0}", ByteConverter.GetString(dataEncoded));

In addition to the selected answer, if you're using .NET 3.5 or .NET 3.5 CE, you have to specify the index of the first byte to decode, and the number of bytes to decode:
string result = System.Text.Encoding.UTF8.GetString(byteArray, 0, byteArray.Length);

Alternatively:
var byteStr = Convert.ToBase64String(bytes);

The BitConverter class can be used to convert a byte[] to string.
var convertedString = BitConverter.ToString(byteAttay);
Documentation of BitConverter class can be fount on MSDN.

To my knowledge none of the given answers guarantee correct behavior with null termination. Until someone shows me differently I wrote my own static class for handling this with the following methods:
// Mimics the functionality of strlen() in c/c++
// Needed because niether StringBuilder or Encoding.*.GetString() handle \0 well
static int StringLength(byte[] buffer, int startIndex = 0)
{
int strlen = 0;
while
(
(startIndex + strlen + 1) < buffer.Length // Make sure incrementing won't break any bounds
&& buffer[startIndex + strlen] != 0 // The typical null terimation check
)
{
++strlen;
}
return strlen;
}
// This is messy, but I haven't found a built-in way in c# that guarentees null termination
public static string ParseBytes(byte[] buffer, out int strlen, int startIndex = 0)
{
strlen = StringLength(buffer, startIndex);
byte[] c_str = new byte[strlen];
Array.Copy(buffer, startIndex, c_str, 0, strlen);
return Encoding.UTF8.GetString(c_str);
}
The reason for the startIndex was in the example I was working on specifically I needed to parse a byte[] as an array of null terminated strings. It can be safely ignored in the simple case

A LINQ one-liner for converting a byte array byteArrFilename read from a file to a pure ASCII C-style zero-terminated string would be this: Handy for reading things like file index tables in old archive formats.
String filename = new String(byteArrFilename.TakeWhile(x => x != 0)
.Select(x => x < 128 ? (Char)x : '?').ToArray());
I use '?' as the default character for anything not pure ASCII here, but that can be changed, of course. If you want to be sure you can detect it, just use '\0' instead, since the TakeWhile at the start ensures that a string built this way cannot possibly contain '\0' values from the input source.

Try this console application:
static void Main(string[] args)
{
//Encoding _UTF8 = Encoding.UTF8;
string[] _mainString = { "Hello, World!" };
Console.WriteLine("Main String: " + _mainString);
// Convert a string to UTF-8 bytes.
byte[] _utf8Bytes = Encoding.UTF8.GetBytes(_mainString[0]);
// Convert UTF-8 bytes to a string.
string _stringuUnicode = Encoding.UTF8.GetString(_utf8Bytes);
Console.WriteLine("String Unicode: " + _stringuUnicode);
}

Here is a result where you didn’t have to bother with encoding. I used it in my network class and send binary objects as string with it.
public static byte[] String2ByteArray(string str)
{
char[] chars = str.ToArray();
byte[] bytes = new byte[chars.Length * 2];
for (int i = 0; i < chars.Length; i++)
Array.Copy(BitConverter.GetBytes(chars[i]), 0, bytes, i * 2, 2);
return bytes;
}
public static string ByteArray2String(byte[] bytes)
{
char[] chars = new char[bytes.Length / 2];
for (int i = 0; i < chars.Length; i++)
chars[i] = BitConverter.ToChar(bytes, i * 2);
return new string(chars);
}

string result = ASCIIEncoding.UTF8.GetString(byteArray);