// </snippet28>
// <snippet24>
// This method is invoked via the AsyncOperation object,
// so it is guaranteed to be executed on the correct thread.
private void CalculateCompleted(object operationState)
{
CalculatePrimeCompletedEventArgs e =
operationState as CalculatePrimeCompletedEventArgs;
OnCalculatePrimeCompleted(e);
}
protected void OnCalculatePrimeCompleted(
CalculatePrimeCompletedEventArgs e)
{
if (CalculatePrimeCompleted != null)
{
CalculatePrimeCompleted(this, e);
}
}
// </snippet40>
// <snippet12>
// This event handler updates the ListView control when the
// PrimeNumberCalculator raises the CalculatePrimeCompleted
// event. The ListView item is updated with the appropriate
// outcome of the calculation: Canceled, Error, or result.
private void primeNumberCalculator1_CalculatePrimeCompleted(
object sender,
CalculatePrimeCompletedEventArgs e)
{
Guid taskId = (Guid)e.UserState;
if (e.Cancelled)
{
string result = "Canceled";
ListViewItem lvi = UpdateListViewItem(taskId, result);
if (lvi != null)
{
lvi.BackColor = Color.Pink;
lvi.Tag = null;
}
}
else if (e.Error != null)
{
string result = "Error";
ListViewItem lvi = UpdateListViewItem(taskId, result);
if (lvi != null)
{
lvi.BackColor = Color.Red;
lvi.ForeColor = Color.White;
lvi.Tag = null;
}
}
else
{
bool result = e.IsPrime;
ListViewItem lvi = UpdateListViewItem(
taskId,
result,
e.FirstDivisor);
if (lvi != null)
{
lvi.BackColor = Color.LightGray;
lvi.Tag = null;
}
}
}
// </snippet24>
// <snippet26>
// This is the method that the underlying, free-threaded
// asynchronous behavior will invoke. This will happen on
// an arbitrary thread.
private void CompletionMethod(
int numberToTest,
int firstDivisor,
bool isPrime,
Exception exception,
bool canceled,
AsyncOperation asyncOp)
{
// If the task was not previously canceled,
// remove the task from the lifetime collection.
if (!canceled)
{
lock (userStateToLifetime.SyncRoot)
{
userStateToLifetime.Remove(asyncOp.UserSuppliedState);
}
}
// Package the results of the operation in a
// CalculatePrimeCompletedEventArgs.
CalculatePrimeCompletedEventArgs e =
new CalculatePrimeCompletedEventArgs(
numberToTest,
firstDivisor,
isPrime,
exception,
canceled,
asyncOp.UserSuppliedState);
// End the task. The asyncOp object is responsible
// for marshaling the call.
asyncOp.PostOperationCompleted(onCompletedDelegate, e);
// Note that after the call to OperationCompleted,
// asyncOp is no longer usable, and any attempt to use it
// will cause an exception to be thrown.
}