// Three things to note in the signature:
// - The method has an async modifier.
// - The return type is Task or Task<T>. (See "Return Types" section.)
// Here, it is Task<int> because the return statement returns an integer.
// - The method name ends in "Async."
async Task <StringBuilder> AccessTheWebAsync(CancellationToken token)
{
if (token.IsCancellationRequested)
{
return(new StringBuilder("cancelled"));
}
// You need to add a reference to System.Net.Http to declare client.
var client = new HttpClient();
// GetStringAsync returns a Task<string>. That means that when you await the
// task you'll get a string (urlContents).
var tsk = client.GetAsync("http://msdn.microsoft.com", token);
// You can do work here that doesn't rely on the string from GetStringAsync.
OutputResultControl.AppendText("Working . . . . . . ." + Environment.NewLine);
if (token.IsCancellationRequested)
{
return(new StringBuilder("cancelled"));
}
// The await operator suspends AccessTheWebAsync.
// - AccessTheWebAsync can't continue until getStringTask is complete.
// - Meanwhile, control returns to the caller of AccessTheWebAsync.
// - Control resumes here when getStringTask is complete.
// - The await operator then retrieves the string result from getStringTask.
var response = await tsk;
string urlContents = await response.Content.ReadAsStringAsync();
// The return statement specifies an integer result.
// Any methods that are awaiting AccessTheWebAsync retrieve the length value.
return(new StringBuilder(urlContents));
}
private async void SqrtLoad_Click(object sender, RoutedEventArgs e)
{
if (((Button)sender).Content.ToString() == "Cancel")
{
GetCanellationtokenForButton((Button)sender).Cancel();
return;
}
var prev = ((Button)sender).Content;
try
{
((Button)sender).Content = "Cancel";
int.TryParse(OutputResultControl.Text, out int count);
var sum = await ComputeStuffAsync(count > 0?(int?)count : null,
GetCanellationtokenForButton((Button)sender).Token);
OutputResultControl.AppendText($"Sqrt sum = {sum} {Environment.NewLine}");
}
catch (Exception ex)
{
//Show error
OutputResultControl.Text = "Error: " + ex.Message;
}
finally
{
((Button)sender).Content = prev;
var cts = GetCanellationtokenForButton((Button)sender);
if (cts.IsCancellationRequested)
{
cts.Dispose();
_cancellationTokenSource.Remove(((Button)sender).Name);
}
}
}
async Task <StringBuilder> DoWorkAsync(SqlTester data, CancellationToken token)
{
if (token.IsCancellationRequested)
{
return(new StringBuilder("cancelled"));
}
var task = Task.Run(() =>
{
Dispatcher.Invoke(() =>
{
OutputResultControl.AppendText("...working with...." + data.DataBaseType.ToString() + Environment.NewLine);
});
if (token.IsCancellationRequested)
{
return(Task.FromResult(new StringBuilder("cancelled")));
}
return(data.Execute(token));
});
return(await task);
}
private async void Button_Click_1(object sender, RoutedEventArgs e)
{
if (((Button)sender).Content.ToString() == "Cancel")
{
GetCanellationtokenForButton((Button)sender).Cancel();
return;
}
var prev = ((Button)sender).Content;
try
{
OutputResultControl.Text = "starting multipple concurrency test" + Environment.NewLine;
var db_type = SelectedDBaseType;
var tst_type = TestType;
((Button)sender).Content = "Cancel";
int concurrentyCount = ConcurrencyCount.GetValueOrDefault(1);
await Task.Factory.StartNew(() =>
{
try
{
ParallelOptions po = new ParallelOptions();
CancellationToken token = default;
Dispatcher.Invoke(() =>
{
token = GetCanellationtokenForButton((Button)sender).Token;
po.CancellationToken = token;
});
Parallel.For(0, concurrentyCount, po, async(i, pls) =>
{
try
{
var data = new SqlTester(db_type, tst_type);
Dispatcher.Invoke(() =>
{
OutputResultControl.AppendText("starting test #" + i + " with " + data.DataBaseType.ToString() +
Environment.NewLine);
});
var result = await data.Execute(token);
// Display the result. All is ok
Dispatcher.Invoke(() =>
{
OutputResultControl.Text = result.ToString();
});
}
catch (OperationCanceledException)
{
pls.Stop();
Dispatcher.Invoke(() =>
{
OutputResultControl.Text = "cancelled";
});
return;
}
catch (Exception ex)
{
//Show error
Dispatcher.Invoke(() =>
{
OutputResultControl.Text = "Error: " + ex.Message;
});
}
});
}
catch (OperationCanceledException)
{
Dispatcher.Invoke(() =>
{
OutputResultControl.Text = "cancelled";
});
}
finally
{
//All sub-task ended. Notify UI
Dispatcher.Invoke(() =>
{
((Button)sender).Content = prev;
var cts = GetCanellationtokenForButton((Button)sender);
if (cts.IsCancellationRequested)
{
cts.Dispose();
_cancellationTokenSource.Remove(((Button)sender).Name);
}
});
}
});
}
catch (Exception ex)
{
//Show error
OutputResultControl.Text = "Error: " + ex.Message;
}
}
async Task <double> ComputeStuffAsync(int?inputCount, CancellationToken token)
{
var tsk = Task.Run(() =>
{
var sum = 0.0;
int DOP = 4;
//var count = inputCount ?? 16;
var count = inputCount ?? 4 * (100 * 1000 * 1000);
long full_range = count / DOP;
long reminder = count % DOP + 1;
if (full_range > 0)
{
Parallel.For(0, DOP, new ParallelOptions {
MaxDegreeOfParallelism = DOP, CancellationToken = token
},
// Initialize the local states
() => 0.0,
// Accumulate the thread-local computations in the loop body
(th, loop, localState) =>
{
long from = full_range * (th);
long to = full_range * (th + 1) - 1;
var computed = calc(from, to, loop);
//Dispatcher.Invoke(() =>
//{
// OutputResultControl.AppendText($" th = {th}, from = {from}, to = {to}, computed = {computed} {Environment.NewLine}");
//});
return(localState + computed);
},
// Combine all local states
localState => Interlocked.Exchange(ref sum, sum + localState)
);
}
if (reminder > 0)
{
long from = full_range * DOP;
long to = from + reminder - 1;
var computed = calcReminder(from, to);
sum += computed;
}
return(sum);
}, token);
return(await tsk);
//priv function
double calc(long from, long to, ParallelLoopState loop)
{
double sum = 0;
for (long i = from; i <= to && !loop.ShouldExitCurrentIteration; i++)
{
sum += Math.Sqrt(i);
//sum += Approximate.Sqrt(i);
//sum += Approximate.Isqrt(i);
}
Dispatcher.Invoke(() =>
{
OutputResultControl.AppendText($" from = {from}, to = {to}, sum = {sum} {Environment.NewLine}");
});
return(sum);
}
double calcReminder(long from, long to)
{
double sum = 0;
for (long i = from; i <= to && !token.IsCancellationRequested; i++)
{
sum += Math.Sqrt(i);
//sum += Approximate.Sqrt(i);
//sum += Approximate.Isqrt(i);
}
Dispatcher.Invoke(() =>
{
OutputResultControl.AppendText($" from = {from}, to = {to}, sum = {sum} {Environment.NewLine}");
});
return(sum);
}
}
