Sockets, Async vs Synch - Freezing Problem

write2jey

Hi, I built a FTP client just for pratice in C#. I'm using synchronous sockets in blocking mode in a while loop in windows forms. So, everytime I'm doing a file transfer the program freezes till it's completely done. Functinoality of the sw is achieved but has this freezing effect persists during transfers. Is this due to the fact the receive/send method in while loop? Could this be avoided using asynchronous sockets? Simply, is that normal for a program to freeze while running in a while loop continuously receiving bytes? But it works. Thank you. JJ

5 Replies

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alobiuc21y ago
Glad to hear it worked out. You're welcome.
write2jey21y ago
hey A.L, Don't get me wrong. Your suggestion did work - separating the main parent thread which handles the GUI and utility methods and putting them in a separate thread. The half sec. freezing problem may be normal because the socket has to resolve the DNS and other overhead call setup stuff. Thanks again! JJ
alobiuc21y ago
I think the half second freeze when calling Connect method it's normal because, especially on slower connection environments, the connection cannot be made instantly (there are a set of operations that must be performed in order to establish a connection between a remote and a local machine, operations the regular user is not aware of; the packets transmitted require a certain amount of time to reach their destination). Yet, I'm surprised that using a separate thread didn't work...anyways, maybe I'm missing something...there are more experienced programmers than me in this forum that may help you. Good luck anyway!
write2jey21y ago
Great! It did solve the problem. Thank you! I don't know if you're experienced in this part of things, but I still have 1/2 second freeze occuring for the intitial Socket.Connect method when it's actually connecting to the server. A separate thread didn't help solve the problem for that. Any ideas? Ur response actually helped earlier. JJ
alobiuc21y ago
Yes, I think the freezing it's normal because both the receiving of the data (the while loop that is) and the GUI operations (the painting process of the window, its movement, etc.) happen in the same thread (the default one) and the while loop is consuming all the CPU time allocated for that thread until it finishes. The solution would be either using asynchronous method or creating a separate thread which would take care of the data transfer.