Wait for a void async method

Question

How can I wait for a void async method to finish its job   for example  I have a function like below   async void LoadBlahBlah         await blah                now I want to make sure that everything has been loaded before continuing somewhere else

User · Answer

You don t really need to do anything manually  await keyword pauses the function execution until blah   returns    private async void SomeFunction          var x   await LoadBlahBlah     lt - Function is not paused        rest of the code get s executed even if LoadBlahBlah   is still executing    private async Task lt T gt  LoadBlahBlah          await DoStuff      lt - function is paused      await DoMoreStuff        T is type of object blah   returns  You can t really await a void function so LoadBlahBlah   cannot be void

User · Answer

If you can change the signature of your function to async Task then you can use the code presented here

User · Answer

Best practice is to mark function async void only if it is fire and forget method  if you want to await on  you should mark it as async Task   In case if you still  want to await  then wrap it like so await Task Run      gt  blah

User · Answer

do a AutoResetEvent  call the function then wait on AutoResetEvent and then set it inside async void when you know it is done   You can also wait on a Task that returns from your void async

User · Answer

The best solution is to use async Task  You should avoid async void for several reasons  one of which is composability   If the method cannot be made to return Task  e g   it s an event handler   then you can use SemaphoreSlim to have the method signal when it is about to exit  Consider doing this in a finally block

User · Answer

I know this is an old question  but this is still a problem I keep walking into  and yet there is still no clear solution to do this correctly when using async await in an async void signature method   However  I noticed that  Wait   is working properly inside the void method   and since async void and void have the same signature  you might need to do the following   void LoadBlahBlah         blah   Wait      this blocks     Confusingly enough async await does not block on the next code   async void LoadBlahBlah         await blah      this does not block     When you decompile your code  my guess is that async void creates an internal Task  just like async Task   but since the signature does not support to return that internal Tasks  this means that internally the async void method will still be able to  await  internally async methods  but externally unable to know when the internal Task is complete   So my conclusion is that async void is working as intended  and if you need feedback from the internal Task  then you need to use the async Task signature instead   hopefully my rambling makes sense to anybody also looking for answers   Edit   I made some example code and decompiled it to see what is actually going on   static async void Test         await Task Delay 5000      static async Task TestAsync         await Task Delay 5000       Turns into  edit  I know that the body code is not here but in the statemachines  but the statemachines was basically identical  so I didn t bother adding them   private static void Test          lt Test gt d  1 stateMachine   new  lt Test gt d  1        stateMachine  lt  gt t  builder   AsyncVoidMethodBuilder Create        stateMachine  lt  gt 1  state   -1      AsyncVoidMethodBuilder  lt  gt t  builder   stateMachine  lt  gt t  builder       lt  gt t  builder Start ref stateMachine     private static Task TestAsync          lt TestAsync gt d  2 stateMachine   new  lt TestAsync gt d  2        stateMachine  lt  gt t  builder   AsyncTaskMethodBuilder Create        stateMachine  lt  gt 1  state   -1      AsyncTaskMethodBuilder  lt  gt t  builder   stateMachine  lt  gt t  builder       lt  gt t  builder Start ref stateMachine       return stateMachine  lt  gt t  builder Task      neither AsyncVoidMethodBuilder or AsyncTaskMethodBuilder actually have any code in the Start method that would hint of them to block  and would always run asynchronously after they are started   meaning without the returning Task  there would be no way to check if it is complete    as expected  it only starts the Task running async  and then it continues in the code  and the async Task  first it starts the Task  and then it returns it   so I guess my answer would be to never use async void  if you need to know when the task is done  that is what async Task is for

[c#] Wait for a void async method

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