private static async IAsyncEnumerable <int> CoroutineA(
[EnumeratorCancellation] CancellationToken token)
{
var inputIdler = new InputIdler();
for (int i = 0; i < 80; i++)
{
// yield to the event loop to process any keyboard/mouse input first
await inputIdler.Yield(token);
// now we could use Task.Run for this
// but let's pretend this code must execute on the UI thread
Console.SetCursorPosition(0, 0);
Console.Write($"{nameof(CoroutineA)}: {new String('A', i)}");
yield return(i);
}
}
private static async IAsyncEnumerable <int> CoroutineB(
[EnumeratorCancellation] CancellationToken token)
{
var inputIdler = new InputIdler();
for (int i = 0; i < 80; i++)
{
// yield to the event loop to process any keyboard/mouse input first
await inputIdler.Yield(token);
Console.SetCursorPosition(0, 1);
Console.Write($"{nameof(CoroutineB)}: {new String('B', i)}");
// slow down CoroutineB
await Task.Delay(25, token);
yield return(i);
}
}
private Form CreateUI()
{
var form = new Form
{
Text = Application.ProductName,
Width = 800, Height = 400,
StartPosition = FormStartPosition.CenterScreen
};
var textBox = new TextBox
{
Multiline = true,
AcceptsReturn = true,
Dock = DockStyle.Fill
};
form.Controls.Add(textBox);
var menu = new MenuStrip {
Dock = DockStyle.Top
};
var actionMenu = new ToolStripMenuItem("Coroutines");
menu.Items.Add(actionMenu);
var actionItems = actionMenu.DropDownItems;
actionItems.Add(
"IEnumerable/Pull-based coroutines", null,
StartCoroutineDemo);
actionItems.Add(
"IAsyncEnumerable/Push-based coroutines", null,
StartAsyncCoroutineDemo);
actionItems.Add(
"IAsyncEnumerable/Push-based mutual coroutines", null,
StartAsyncCoroutineDemoMutual);
menu.Items.Add(
"Stop", null, (s, e) => Stop());
menu.Items.Add(
"Close", null, (s, e) => form.Close());
CancellationTokenSource?uiWorkCts = null;
menu.Items.Add(
"Show TickCount", null, async(s, e) => {
// not good: do some silly work on the UI thread in a hot loop
uiWorkCts?.Cancel();
uiWorkCts = CancellationTokenSource.CreateLinkedTokenSource(Token);
uiWorkCts.CancelAfter(5000);
var idler = new InputIdler();
while (!uiWorkCts.Token.IsCancellationRequested)
{
textBox.Text = $"TickCount: {Environment.TickCount}";
form.Refresh();
if (InputIdler.AnyInputMessage())
{
// process messages
await idler.Yield(CancellationToken.None);
}
}
textBox.Text = String.Empty;
});
form.MainMenuStrip = menu;
form.Controls.Add(menu);
form.FormClosing += (s, e) => Stop();
return(form);
}