private Decimal Calculate(CalcShippingAsyncArgs parameters)
{
Decimal result = 0;
Boolean isFreeShipping = false;
System.Threading.Thread.Sleep(500); //simulate a short delay
switch (parameters.ShipVia)
{
case "normal":
if (parameters.OrderTotal >= _freeThreshold)
{
isFreeShipping = true;
}
else
{
result = parameters.Weight * _normalRate;
}
break;
case "express":
result = parameters.Weight * _expressRate;
break;
}
if ((result < _minimum) && (!isFreeShipping))
{
result = _minimum;
}
return(result);
}
protected override IAsyncResult BeginExecute(
AsyncCodeActivityContext context,
AsyncCallback callback, object state)
{
CalcShippingAsyncArgs parameters = new CalcShippingAsyncArgs
{
Weight = Weight.Get(context),
OrderTotal = OrderTotal.Get(context),
ShipVia = ShipVia.Get(context),
};
Func <CalcShippingAsyncArgs, Decimal> asyncWork = a => Calculate(a);
context.UserState = asyncWork;
return(asyncWork.BeginInvoke(parameters, callback, state));
}
