如何从SerialPort.BaseStream读取没有长度的字节

Question

I want to use the stream class to read/write data to/from a serial port. I use the BaseStream to get the stream (link below) but the Length property doesn't work. Does anyone know how can I read the full buffer without knowing how many bytes there are?

http://msdn.microsoft.com/en-us/library/system.io.ports.serialport.basestream.aspx

Answer 1

You can't. That is, you can't guarantee that you've received everything if all you have is the BaseStream .

There are two ways you can know if you've received everything:

1. Send a length word as the first 2 or 4 bytes of the packet. That says how many bytes will follow. Your reader then reads that length word, reads that many bytes, and knows it's done.
2. Agree on a record separator. That works great for text. For example you might decide that a null byte or a end-of-line character signals the end of the data. This is somewhat more difficult to do with arbitrary binary data, but possible. See comment.

Or, depending on your application, you can do some kind of timing. That is, if you haven't received anything new for X number of seconds (or milliseconds?), you assume that you've received everything. That has the obvious drawback of not working well if the sender is especially slow.

Answer 2

也许您可以尝试SerialPort.BytesToRead属性。