private async Task Do1AsyncWrapper(string buttonName, string self, Label label, bool innerConfigureAwait)
{
var target = $"await {nameof(AsyncSample.Do1Async)}()";
Helper.Log($"{buttonName} {self} : begin");
// label.Textを後続で呼び出すためUIスレッドである必要がある。
// この呼び出しはConfigureAwait(true)である必要がある。
await AsyncSample.Do1Async(buttonName, 1000, innerConfigureAwait);
label.Text = $"{buttonName} completed at {DateTime.Now.ToString("HH:mm:ss.fff")}";
Helper.Log($"{buttonName} {self} : end");
}
// Project > build > advanced settings > Language Version > latest miner(C#7.1 <=)
// "async Task Main" is alias for Task.GetAwaiter().GetResult()
static async Task Main(string[] args)
{
Console.WriteLine("Press d or else.");
var key = Console.ReadKey();
Console.WriteLine();
if (key.Key == ConsoleKey.D)
{
/*
* If raisesDeadLock mode, deadlock!
* Reason
* https://stackoverflow.com/questions/58960005/async-await-deadlock-when-using-windowsformssynchronizationcontext-in-a-console
*
* 1.
* WindowsFormsSynchronizationContext depends on Win32 message loop.
* But, console application don't start it.
* Win32 message loop is started by the followings.
* A. C# Application.Run()
* B. C++ LRESULT CALLBACK WndProc()
*
* 2.
* new Form() or other controls, switchs SynchronizationContext to WindowsFormsSynchronizationContext.
* (WindowsFormsSynchronizationContext.AutoInstall = true)
*
* 3.
* Program is WindowsFormsSynchronizationContext mode, but it don't start Win32 message loop.
* In this state, WindowsFormsSynchronizationContext.Post() (It is called by completing of await) don't work.
*/
Console.WriteLine("Deadlock sample.");
Helper.Log("before new From : Current=" + System.Threading.SynchronizationContext.Current);
var frm = new System.Windows.Forms.Form();
Helper.Log("after new From : Current=" + System.Threading.SynchronizationContext.Current);
await Task.Delay(1000); // dead lock!
}
Helper.Log();
Helper.Log("1st begin.");
await AsyncSample.Do1Async("1st", 500, true);
Helper.Log("1st end.");
Helper.Log("2nd begin.");
await AsyncSample.Do1Async("2nd", 1000, true);
Helper.Log("2nd end.");
Helper.Log("3rd begin.");
await AsyncSample.Do1Async("3rd", 1500, true);
Helper.Log("3rd end.");
Console.WriteLine("All complete.");
Console.ReadKey();
}