private void Worker(T arg, AsyncOperation asyncOp)
{
TResult result = default(TResult);
Exception error = null;
bool cancelled;
if (!Cancelled(asyncOp.UserSuppliedState))
{
try {
result = _func(arg, () => Cancelled(asyncOp.UserSuppliedState), (p) => ReportProgressChanged(p, asyncOp));
} catch (Exception ex) {
error = ex;
}
}
cancelled = Cancelled(asyncOp.UserSuppliedState);
if (!cancelled)
{
lock (_userStateToLifetime.SyncRoot) {
_userStateToLifetime.Remove(asyncOp.UserSuppliedState);
}
}
AsyncFuncCompletedEventArgs <TResult> e = new AsyncFuncCompletedEventArgs <TResult>(result, error, cancelled, asyncOp.UserSuppliedState);
asyncOp.PostOperationCompleted(_onCompleted, e);
}
private void CompletedCallback(object operationState)
{
AsyncFuncCompletedEventArgs <TResult> e = (AsyncFuncCompletedEventArgs <TResult>)operationState;
AsyncFuncCompletedEventHandler <TResult> snapshot = Completed;
if (snapshot != null)
{
snapshot(Sender, e);
}
}
private void Worker(T arg, AsyncOperation asyncOp)
{
// 进入这个方法表示异步调用已完成。
// 设置标志变量，确保只调用一次，不管是正常完成的回调还是超时回调。
if (Interlocked.CompareExchange(ref _status, 1, 0) == 1)
{
DisposeTimer();
_isBusy = true;
return;
}
TResult result = default(TResult);
Exception error = null;
try {
if (!_isCancelled)
{
// Check if function can check for cancellation
Func <bool> isCancelled = null;
if (_isCancellable)
{
isCancelled = () => _isCancelled;
}
// Check if function can report progress
Action <int> reportProgress = null;
if (_onProgressChanged != null)
{
reportProgress = (p) => ReportProgressChanged(p, asyncOp);
}
// Invoke function synchronously
result = _func(arg, isCancelled, reportProgress);
}
} catch (Exception ex) {
error = ex;
} finally {
DisposeTimer();
_isBusy = false;
AsyncFuncCompletedEventArgs <TResult> e = new AsyncFuncCompletedEventArgs <TResult>(result, error, _isCancelled, null);
asyncOp.PostOperationCompleted(_onCompleted, e);
Interlocked.CompareExchange(ref _status, 0, 1);
}
}
