Asynchronously wait for Task<T> without async/await

2
votes

I want my Task to complete before I perform other actions. If I use 

Task.WaitAll(task);

it certainly blocks my UI thread. What is the best way to wait asynchronously for a Task to complete, without using async / await (I'm using .NET v4.0)?

1
c#asynchronoustask-parallel-library
The concept of waiting asynchronously is hurting my brain... – Matthew Watson
Why not just run it synchronously? – doctorlove
You can only compose continuations (ContinueWith). That being said, you can use async & await and target .NET 4. You have to use VS2012 though, with Async Targeting Pack. – Patryk Ćwiek
what's the point of making asynchronous calls if it's to wait for them to complete. It's same thing as taking a 1 lane road split it to 8 lane and come back 1 lane. – Franck
Hmm, if you really mean "how do I call a method when a certain task has completed", then @user2834880 has the right answer. – Matthew Watson

1 Answers

7
votes

You can use async / await also in .NET 4.0 when you add the Microsoft.Bcl.Async NuGet package to your project. Besides this, you have not much choice - either you use asynchronous calls or your block your thread with the method you mentioned already.

However, you're not bound to await when using asynchronous method. You can also use a callback:

task.ContinueWith(r => {
    /* code */
});