Autocomplete: Asynchronous population with WCF using threads

Question

I have an "autocomplete" textbox that will invoke a WCF method each time a key is pressed. The WCF server, in turn, will run an SQL query, return the first 15 results and send them. However, this results in a noticeable latency when typing in the box.

What I'm about to do instead is this:

• Create a new thread when a text_changed event is fired, make that thread wait 1000ms using Stopwatch.ElapsedMilliseconds. During this waiting time, the thread can be stopped permanently.
• If it was not stopped, the thread will send the request to the server (and repopulate the auto complete box).
• As soon as a new "text_changed" event is fired, I will stop the current thread and start a new one.

Is there a better approach or is this the way to go?

Answer 1

So basically wait for 1 second for the user to stop typing before requesting results.

That's a good solution for conserving server resources, but you are actually adding latency by making the user wait for a minimum of 1000ms.

My guess is that your original issue was that this is a winforms app and the request you made was synchronous by default. As a result, the textbox wasn't accepting user input while the app was waiting for a response. Just making the call asynchronous should solve that issue without making the typing slower.