/// <summary>
/// Example of using async/await to add threading (non-blocking) to our app.
///
/// Can you see how these are basically doing the same thing?
/// </summary>
private async Task DoWorkWithAsync()
{
txtLog.Clear();
var watch = new Stopwatch();
watch.Start();
// let user know we're working...
statusLabel.Text = "Processing payment...";
// call slow API
var chargeResults = await Task.Run(() => SlowApiCall.ProcessPayment());
// update UI with results
txtLog.AppendText($"Process Payment Results: {chargeResults}{Environment.NewLine}");
// let user know we're saving to the database
statusLabel.Text = "Saving to database...";
// call database with results from API
var dbResults = await Task.Run(() => SlowDatabase.LogCharge(chargeResults));
// update UI with results
txtLog.AppendText($"Database Results: {dbResults}{Environment.NewLine}");
statusLabel.Text = "DONE!";
txtLog.AppendText($"Done!{Environment.NewLine}{Environment.NewLine}");
watch.Stop();
txtTotalTime.Text = watch.Elapsed.ToString();
}
/// <summary>
/// This call will block the UI thread... it also shows off the C# yield statement
/// </summary>
private void btnDoWorkNormal_Click(object sender, EventArgs e)
{
txtLog.Clear();
var watch = new Stopwatch();
watch.Start();
// let user know we're working...
statusLabel.Text = "Processing payment...";
// call slow API
var chargeResults = SlowApiCall.ProcessPayment();
// update UI with results
txtLog.AppendText($"Process Payment Results: {chargeResults}{Environment.NewLine}");
statusLabel.Text = "Saving to database...";
// call database with results from API
var dbResults = SlowDatabase.LogCharge(chargeResults);
// update UI
txtLog.AppendText($"Database Results: {dbResults}{Environment.NewLine}");
statusLabel.Text = "DONE!";
txtLog.AppendText($"Done!{Environment.NewLine}{Environment.NewLine}");
watch.Stop();
txtTotalTime.Text = watch.Elapsed.ToString();
}
private void btnNonBlockedUIManual_Click(object sender, EventArgs e)
{
txtLog.Clear();
var watch = new Stopwatch();
watch.Start();
// let user know we're working...
statusLabel.Text = "Processing payment...";
// call slow API
Task.Run(() => SlowApiCall.ProcessPayment())
.ContinueWith(prevTask =>
{
var chargeResults = prevTask.Result;
AsyncHelper.BeginOnUIThread(() =>
{
// update UI with results
txtLog.AppendText($"Process Payment Results: {chargeResults}{Environment.NewLine}");
// let user know we're working
statusLabel.Text = "Saving to database...";
});
// call database with results from API
return(SlowDatabase.LogCharge(chargeResults));
}).ContinueWith(prevTask =>
{
// call database with results from API
var dbResults = prevTask.Result;
AsyncHelper.BeginOnUIThread(() =>
{
// update UI
txtLog.AppendText($"Database Results: {dbResults}{Environment.NewLine}");
statusLabel.Text = "DONE!";
txtLog.AppendText($"Done!{Environment.NewLine}{Environment.NewLine}");
watch.Stop();
txtTotalTime.Text = watch.Elapsed.ToString();
});
});
}
/// <summary>
/// Example of using continuations (with coroutines) to add threading (non-blocking) to our app.
///
/// Still using yield return, but our caller doesn't just enumerate the results
/// because we don't want to block the UI. However, we're not having to use callbacks here.
///
/// Why not?
///
/// See AsyncResult code + the calling code. This ideas was popularized in .NET by the Caliburn
/// library (which Deployer uses).
/// </summary>
private IEnumerable <IResult> DoWorkWithManualContinuations()
{
txtLog.Clear();
var watch = new Stopwatch();
watch.Start();
// let user know we're working...
statusLabel.Text = "Processing payment...";
string chargeResults = null;
// call slow API
yield return(new AsyncResult <string>(
action: SlowApiCall.ProcessPayment,
callback: x => chargeResults = x,
errorCallback: ex => MessageBox.Show(ex.ToString())));
// update UI with results
txtLog.AppendText($"Process Payment Results: {chargeResults}{Environment.NewLine}");
// let user know we're working...
statusLabel.Text = "Saving to database...";
string dbResults = null;
// call database with results from API
yield return(new AsyncResult <string>(
action: () => SlowDatabase.LogCharge(chargeResults),
callback: x => dbResults = x,
errorCallback: ex => MessageBox.Show(ex.ToString())));
// update UI
txtLog.AppendText($"Database Results: {dbResults}{Environment.NewLine}");
statusLabel.Text = "DONE!";
txtLog.AppendText($"Done!{Environment.NewLine}{Environment.NewLine}");
watch.Stop();
txtTotalTime.Text = watch.Elapsed.ToString();
}
