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SignalR client and WinRT: do not call Wait () when starting ()

I have a question regarding the official SignalR documentation - Hubs-.NET Client Feature Guide . In the section - How to establish a connection . The following was written:

The start method runs asynchronously. To ensure that subsequent lines of code are not executed until the connection is established, use the ASP.NET 4.5 or .Wait () method in the synchronous method in the asynchronous method. Do not use .Wait () in the WinRT client.

Does anyone know what is the specific reason not to call Wait ()? In addition, this also applies when I have a WinRT client, where do I have a call from hubProxy.Invoke() to the server?

Thank you for your help!

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From the comment:

There is nothing mentioned regarding asynchronous or synchronous code. Is WinRT code asynchronous by default or is there something else I don't know or don't understand?

There are at least two reasons for not blocking the client user interface (including WinRT):

  • Avoid blocking the user interface and maintain it freely
  • avoid the deadlocks described in Steven Cleary's blog when there is await in the current call chain to the top stack of the frame;

The latter is especially important for WinRT, where asynchrony is common. The entire WinRT infrastructure was designed as "async all the way down" , so it is very likely that you will create a dead end if you use task.Wait or task.Result anywhere in the user interface stream.

There are also at least two reasons for an ASP.NET server application not to block:

  • Lock
  • makes your web application less scalable because a blocked stream may serve other incoming HTTP requests.
  • same deadlock scenario.

You can view the list of links in the async-await wiki for further reading.

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