C# - FileStream: both lock a file and at the same time be able to read it without truncating it and write it with truncating it

Question

I suppose my title isn\'t that clear.

I\'ll try to explain:

I can write and read a file using a FileStream

FileStream fs = new FileStream(\"C         


        

Answer 1

In your first example, you need to reset the stream before you write to it in order to replace the file contents, instead of appending to it:

private void button2_Click(object sender, EventArgs e)
{
    fs.Seek(0,0);
    fs.SetLength(Encoding.UTF8.GetBytes(textbox.Text).Length));
    StreamWriter sw = new StreamWriter(fs);
    sw.Write(textbox.Text);
    sw.Flush();
}

Answer 2

If you truncate the stream down to 0, it will also work and no need to calculate the new file size in bytes.

fs.Seek(0,0);
fs.SetLength(0);