How to Read First 512 Bytes of data from a .dat file in C#?

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H,

How to Read First 512 Bytes of data from a .dat file in C# ? My dat files contains binary data. I am using File.ReadAllBytes currently to read data from the dat file.But it Reads all the data, i want to read only first 512 bytes then break. I need to use for loop for this or any other approach. Any help is appreciated.

You can try this:

byte[] buffer = new byte[512];
try
{
     using (FileStream fs = new FileStream(filename, FileMode.Open, FileAccess.Read))
     {
          fs.Read(buffer, 0, buffer.Length);
          fs.Close();
     }
}
catch (System.UnauthorizedAccessException ex)
{
     Debug.Print(ex.Message);
}

PC Mag, C creates a data file ordered on ASCII keys entered by the user, resulting in TESTFILE .DAT. Figure 3: SRCH IF .C, a C program that performs sequential and binary C. Bytes K512! to (R812!-1) of the record are initialized to zero and are not i, printf('s2d: ', i+l); 1' prompt user for next string '/ gets(sitems[I$IlB v i]); /' read  The following code example shows how to write data to a file, byte by byte, and then verify that the data was written correctly. using namespace System; using namespace System::IO; int main() { String^ fileName = "Test@##@.dat"; // Create random data to write to the file.

You can use a byte[] variable, and FileStream.Read for that.

C: Reading data from a file using fread(), A buffer is a region of memory used to temporarily store data; Size: The size of each element to be read in bytes; Count: Number of elements to be read; Stream:​  I have a program that has an array of bytes containing some data and a file where this data is written. byte[] bytes = new byte[16]; string path = "Dir/File.dat"; Each time when data in the "bytes" array changes, all 16 bytes are written to file: using (var stream = new FileStream(path, FileMode.Append)) { stream.Write(bytes, 0, bytes.Length); }

I believe the easiest, and honestly, most effective approach is this:

            using (BinaryReader br = new BinaryReader(File.OpenRead(openFileDailog1.FileName)))
        {
            br.BaseStream.Seek(0x4D, SeekOrigin.Begin); //Put the beginning of a .dat file here. I put 0x4D, because it's the generic start of a file.
            gameCode = Encoding.UTF8.GetString(br.ReadBytes(512)); //Or whatever string you want
        }
        br.Close();

Hope this helps!

What is wrong with this approach to reading first 512 bytes in , loop to read the first 512 byes for comparison in pset4 recover.c. The first[] array is declared as 512 elements of type LONG. But then, it has an fseek that will move the file pointer forward and skip over data. The resources required to read 1 byte from the file are the same as it takes to read 512 bytes. i said if the file is in .txt i read all teh data, but if the file is in .dat , i can't read all the data CHill60 13-Jun-16 9:33am It doesn't matter if the textbox is multi-line - you are overwriting the entire text on each loop.

File Signatures, This table of file signatures (aka "magic numbers") is a continuing DAT, MapInfo Native Data Format 09 08 10 00 00 06 05 00, [512 (0x200) byte offset] file headers: The signature above is correct for the generic first six bytes. t C/​C++. PDB, Microsoft C++ debugging symbols file. 4D 69 63 72 6F 73  To add to your statement, I even suggest considering async ASP.NET handlers if you have an I/O bound operation like streaming a file to the client. However, if you have to read the whole file to a byte[] for some reason, I suggest avoid using streams or anything else and just use the system provided API. – Mehrdad Afshari Jan 8 '10 at 21:47

How I can read after EOF? C# [closed] - c# - csharp, Is it possible by using C#? How? Removing the first bytes in a file. Is there a way to remove the first few bytes of a file (truncating it from the front) without using DAT files can be anything, they are usually just application data. block it would at least be a sector (512 bytes), probably not a match to the size of your line. dat-get-dim returns the dimensions of the DAT file in the same format. dat-set-type and dat-get-type get and set the sample type of the DAT file. The type is given as a character--see the man pages for a list of accepted types and their corresponding characters. dat-set-key and dat-get-key get and set key values in the DAT file's descriptor

READ_BINARY, Data is read from the given filename or from the current file position in the specifies that a two-dimensional, 512 by 512 array be read and returned. file, READ_BINARY will swap the order of bytes in multi-byte data types read from the file. data in the surface.dat file, found in the examples/data subdirectory of the IDL  Read(Byte[], Int32, Int32) Reads a block of bytes from the stream and writes the data in a given buffer. Read(Span<Byte>) Reads a sequence of bytes from the current file stream and advances the position within the file stream by the number of bytes read.

Comments
  • An unhandled exception of type 'System.UnauthorizedAccessException' occurred in mscorlib.dll
  • @user662285: you're trying to access a file you're not authorized to. Probably you're using Windows Vista or Seven... try to run your exe with higher privileges. Let me know
  • I resolved it . i added FileAccess.Read as third parameter using (FileStream fs = new FileStream(strFileName, FileMode.Open,FileAccess.Read))
  • Check out this page from Jon Skeet why this approach is not a good solution.