Await async C# method from PowerShell

It'll run fine on its own, but if you want to wait for it to finish you can use this

$null = [MyNamespace.MyClass]::MyStaticMethod($myParam).GetAwaiter().GetResult()

This will unwrap the AggregateException that would be thrown if you used something like $task.Result instead.

However that will block until it's complete, which will prevent CTRL + C from properly stopping the pipeline. You can wait for it to finish while still obeying pipeline stops like this

 $task = [MyNamespace.MyClass]::MyStaticMethod($myParam)
 while (-not $task.AsyncWaitHandle.WaitOne(200)) { }
 $null = $task.GetAwaiter().GetResult()

If the async method actually returns something, remove $null =

Borrowing from Patrick Meinecke's answer, it's possible to make a pipeline-able function that will resolve a task (or list of tasks) for you:

function Await-Task {
    param (
        [Parameter(ValueFromPipeline=$true, Mandatory=$true)]
        $task
    )

    process {
        while (-not $task.AsyncWaitHandle.WaitOne(200)) { }
        $task.GetAwaiter().GetResult()
    }
}

Usage:

$results = Get-SomeTasks $paramA $paramB | Await-Task