Hello everyone,
as the title suggests im trying to multitask and also use parallel tasks, however its throwing me this unhandled exception after the first time :
#if DEBUG && !DISABLE_XAML_GENERATED_BREAK_ON_UNHANDLED_EXCEPTION
UnhandledException += (sender, e) =>
{
if (global::System.Diagnostics.Debugger.IsAttached) global::System.Diagnostics.Debugger.Break();
};
#endif
from the app.g.i.cs file..
the first time i click the button in order to run the tasks it completes successfully but when i click the button the second time after it finishes the tasks then it throws me that error..this is just a sample app that im using for testing purposes, i remember
that before i upgraded to Windows 8.1 the app was working perfectly, does Windows 8.1 restricts the cpu usage or something like that? another detail is that when i first built this app i was running it in another machine which i havent tested it again using
Windows 8.1 but this machine where i am receiving this exception is a first generation corei5...not sure if that might be the root cause of the problem..
anyways that said i hope someone can help me out with this and by the way here it is the code :
public sealed partial class GraphWindow : Page
{
// Reduce pixelWidth and pixelHeight if there is insufficient memory available
private int pixelWidth = 12000;
private int pixelHeight = 8000;
private WriteableBitmap graphBitmap = null;
private int bytesPerPixel = 4;
private byte[] data;
private byte redValue, greenValue, blueValue;
private CancellationTokenSource tokenSource = null;
public GraphWindow()
{
this.InitializeComponent();
Window.Current.SizeChanged += App.WindowSizeChanged;
int dataSize = bytesPerPixel * pixelWidth * pixelHeight;
data = new byte[dataSize];
graphBitmap = new WriteableBitmap(pixelWidth, pixelHeight);
}
private void cancelButton_Click(object sender, RoutedEventArgs e)
{
if (tokenSource != null)
{
tokenSource.Cancel();
}
}
private async void plotButton_Click(object sender, RoutedEventArgs e)
{
Random rand = new Random();
redValue = (byte)rand.Next(0xFF);
greenValue = (byte)rand.Next(0xFF);
blueValue = (byte)rand.Next(0xFF);
tokenSource = new CancellationTokenSource();
CancellationToken token = tokenSource.Token;
Stopwatch watch = Stopwatch.StartNew();
try
{
await generateGraphDataAsync(data, 0, pixelWidth / 2, token);
duration.Text = string.Format("Duration (ms): {0}", watch.ElapsedMilliseconds);
}
catch (OperationCanceledException oce)
{
duration.Text = oce.Message;
}
Stream pixelStream = graphBitmap.PixelBuffer.AsStream();
pixelStream.Seek(0, SeekOrigin.Begin);
pixelStream.Write(data, 0, data.Length);
graphBitmap.Invalidate();
graphImage.Source = graphBitmap;
}
private async Task generateGraphDataAsync(byte[] data, int partitionStart, int partitionEnd, CancellationToken token)
{
//Task task = Task.Run(() => generateGraphData(data, partitionStart, partitionEnd, token));
Task first = Task.Run(() => generateGraphData(data, 0, pixelWidth / 4, token), token);
Task second = Task.Run(() => generateGraphData(data, pixelWidth / 4, pixelWidth / 2, token), token);
await first;
await second;
}
private void generateGraphData(byte[] data, int partitionStart, int partitionEnd, CancellationToken token)
{
int a = pixelWidth / 2;
int b = a * a;
int c = pixelHeight / 2;
for (int x = partitionStart; x < partitionEnd; x++)
{
int s = x * x;
double p = Math.Sqrt(b - s);
for (double i = -p; i < p; i += 3)
{
token.ThrowIfCancellationRequested();
double r = Math.Sqrt(s + i * i) / a;
double q = (r - 1) * Math.Sin(24 * r);
double y = i / 3 + (q * c);
plotXY(data, (int)(-x + (pixelWidth / 2)), (int)(y + (pixelHeight / 2)));
plotXY(data, (int)(x + (pixelWidth / 2)), (int)(y + (pixelHeight / 2)));
}
}
}
private void plotXY(byte[] data, int x, int y)
{
int pixelIndex = (x + y * pixelWidth) * bytesPerPixel;
data[pixelIndex] = blueValue;
data[pixelIndex + 1] = greenValue;
data[pixelIndex + 2] = redValue;
data[pixelIndex + 3] = 0xBF;
}
}
so this is not the parallel sample just the Task.Run() but both gives me the same error and the code is pretty similar..
any help is greatly appreciated!
Kind regards,
c# user
