Write bytes to file

Question

I have a hexadecimal string  e g 0CFE9E69271557822FE715A8B3E564BE  and I want to write it to a file as bytes  For example   Offset      0  1  2  3  4  5  6  7   8  9 10 11 12 13 14 15 00000000   0C FE 9E 69 27 15 57 82  2F E7 15 A8 B3 E5 64 BE        i  W             d     How can I accomplish this using  NET and C

User · Answer

Try this   private byte   Hex2Bin string hex      if   hex    null      hex Length  lt  1       return new byte 0       int num   hex Length   2   byte   buffer   new byte num    num    2   for  int i   0  i  lt  num  i        int num3   int Parse hex Substring i  2   NumberStyles HexNumber     buffer i   2     byte  num3    i        return buffer     private string Bin2Hex byte   binary      StringBuilder builder   new StringBuilder     foreach byte num in binary      if  num  gt  15       builder AppendFormat   0 X    num       else      builder AppendFormat  0 0 X    num              15      0         return builder ToString

User · Answer

This example reads 6 bytes into a byte array and writes it to another byte array  It does an XOR operation with the bytes so that the result written to the file is the same as the original starting values  The file is always 6 bytes in size  since it writes at position 0   using System  using System IO   namespace ConsoleApplication1       class Program               static void Main                     byte   b1     1  2  4  8  16  32            byte   b2   new byte 6           byte   b3   new byte 6           byte   b4   new byte 6            FileStream f1          f1   new FileStream  test txt   FileMode Create  FileAccess Write               write the byte array into a new file         f1 Write b1  0  6           f1 Close                read the byte array         f1   new FileStream  test txt   FileMode Open  FileAccess Read            f1 Read b2  0  6           f1 Close                make changes to the byte array         for  int i   1  i  lt  b2 Length  i                          b2 i     byte  b2 i     byte 10     xor 10                    f1   new FileStream  test txt   FileMode Open  FileAccess Write              write the new byte array into the file         f1 Write b2  0  6           f1 Close             f1   new FileStream  test txt   FileMode Open  FileAccess Read               read the byte array         f1 Read b3  0  6           f1 Close                make changes to the byte array         for  int i   1  i  lt  b3 Length  i                          b4 i     byte  b3 i     byte 10     xor 10                    f1   new FileStream  test txt   FileMode Open  FileAccess Write               b4 will have the same values as b1         f1 Write b4  0  6           f1 Close

User · Answer

If I understand you correctly  this should do the trick  You ll need add using System IO at the top of your file if you don t already have it   public bool ByteArrayToFile string fileName  byte   byteArray        try               using  var fs   new FileStream fileName  FileMode Create  FileAccess Write                         fs Write byteArray  0  byteArray Length               return true                      catch  Exception ex                Console WriteLine  Exception caught in process   0    ex           return false

User · Answer

The simplest way would be to convert your hexadecimal string to a byte array and use the File WriteAllBytes method   Using the StringToByteArray   method from this question  you d do something like this   string hexString    0CFE9E69271557822FE715A8B3E564BE    File WriteAllBytes  output dat   StringToByteArray hexString        The StringToByteArray method is included below   public static byte   StringToByteArray string hex        return Enumerable Range 0  hex Length                        Where x   gt  x   2    0                        Select x   gt  Convert ToByte hex Substring x  2   16                         ToArray

User · Answer

You convert the hex string to a byte array   public static byte   StringToByteArray string hex    return Enumerable Range 0  hex Length                    Where x   gt  x   2    0                    Select x   gt  Convert ToByte hex Substring x  2   16                     ToArray        Credit  Jared Par  And then use WriteAllBytes to write to the file system

[c#] Write bytes to file

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