What's the opposite to ChannelFactory<TChannel>.CreateChannel?

Question

I just followed this tutorial and played a little bit with the code. I'm almost sure I read somewhere that there is a timeout for the channel, so it might get automatically closed eventually. So I tried simply opening a new channel in my client for each method I wanted to invoke, and eventually (after lots of calls) I got errors.

Seems like there is a limit on how many channels I can have open at the same time. But since the channel is an instance of a custom object, I don't see how can I close it or kill it or whatever I need to do with it to get rid of it so I can create other channels.

Then I noticed on the CreateChannel documentation that my TChannel should implement IChannel (which the tutorial I linked above doesn't do). So, is this how I would close my channel? If so, how would I close it or what should I do on my implementation of the Close method? And what should I do on the implementation of every other method if I do have to implement the interface?

Or should I just use a single channel for as long as it lasts? Anyway, how am I supposed to know whether is faulted or open or closed if all I have is an instance of my own class?

As you can see I'm pretty lost on the subject so I hope you can point me in the right direction.

Answer 1

ChannelFactory<TChannel>.CreateChannel creates and return a channel of your specified service type. The returned object already implements IChannel. You (normally?) don't need to implement your own Close method, nor any other methods of IChannel.

Normally you don't create a new channel for every call, you just re-use it. (Only in some specific cases it may be better to create a new channel for every call).

You can close the channel by casting it to IClientChannel. Use this pattern:

try
{
  ((IClientChannel)channel).Close();
}
catch (Exception ex)
{
  ((IClientChannel)channel).Abort();
}

You can use ((IClientChannel)channel).State to get the state of the channel (i.e. CreatedOpened, Faulted, Closed).

Answer 2

Peladao basically hits the nail on the head.

To clarify some of what he is saying, CreateChannel will create a (proxy) object which implements both your custom service interface and IClientChannel.

Typically you do keep the channel open and reuse its calls. Beware also that once it enters a fault state there is no recovery, you must open a new channel. As Peladao mentions a fault state can be detected via ((IClientChannel)channel).State, and also don't forget you'll generally get an exception too.

If memory serves, the debug process for WCF accepts 10 simultaneous channels for a service.