C# Append byte array to existing file

c# arrays byte append concatenation

user725913 · Jul 28, 2011 · Viewed 48.2k times · Source

I would like to append a byte array to an already existing file (C:\test.exe). Assume the following byte array:

byte[] appendMe = new byte[ 1000 ] ;

File.AppendAllBytes(@"C:\test.exe", appendMe); // Something like this - Yes, I know this method does not really exist.

I would do this using File.WriteAllBytes, but I am going to be using an ENORMOUS byte array, and System.MemoryOverload exception is constantly being thrown. So, I will most likely have to split the large array up into pieces and append each byte array to the end of the file.

Thank you,

Evan

Answer

One way would be to create a FileStream with the FileMode.Append creation mode.

Opens the file if it exists and seeks to the end of the file, or creates a new file.

This would look something like:

public static void AppendAllBytes(string path, byte[] bytes)
{
    //argument-checking here.

    using (var stream = new FileStream(path, FileMode.Append))
    {
        stream.Write(bytes, 0, bytes.Length);
    }
}

C# Append byte array to existing file

Answer

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