C＃，当主线程空闲时如何在主线程中运行函数

Question

I'm trying to port a Dart application to C#, in my dart app I use Futures to queue up functions asynchronously such that the queue will execute each subsequent function at some point in the future when it's turn comes in the VM's asynchronous call queue but importantly these are run in the "root thread". I understand this is highly specific to the Dart VM, but I was wondering whether anything similar could be done in C#. I basically want to be able to pass a function which takes no arguments to some method or object which will call that function in the main thread when the main thread finds it has no more work to do. I should also say that my code is for a service, not a UI application.

Answer 1

You can do that by creating your own custom SynchronizationContext , Stephen Toub has an article on how to do that here . The SynchronizationContext is what is used to schedule work to be done. So by rolling your own, you need to keep a queue of the work to be done and then execute each action in the queue.

You can customize this so that when the queue is empty (ie the SynchronizationContext is idle) you execute the action that you need. More info on contexts here .

An effective way to send something to be executed to a particular SyncrhonizationContext is to use Task.Run . The code below will schedule your code to run in the current SC. Using Task.Run without specifying a TaskScheduler will schedule the work on a thread pool thread.

Task.Run( () =>/* you code */, CancellationToken.None, TaskScheduler.FromCurrentSynchronizationContext());