How to append data using just BinaryWriter at the end of the file?

Question

Maybe similar questions were asked in Stackoverflow, but I seem not to be able to find a solution to my problem.

I simply want to open a writable binary stream and be able to append data to the file using the same stream. Apparently, if you open a file for writing, it will erase all the data that it contained and start a new one. Plus, if you open a file for just reading, you can't write but only read. People did suggest online to use two separate stream - one for reading and the other for writing. I don't think that will work in this case.

Take a look at my sample code, I want to do something similar :

fs:BinaryWriter;

fs := new BinaryWriter(File.Create('c:\test.dat'));

fs.seek(0,SeekOrigin.End);

fs.Write('test string');

fs.Close;

Answer 1

If you open the writer like this

Stream fs = new FileStream(filename, FileMode.Append);
BinaryWriter bw = new BinaryWriter(fs);

it should open in append mode.