private async Task FetchStocksAsync()
{
try
{
fetchButton.Enabled = false;
Log("Authenticating");
Task <Guid?> authTask = authenticationService.AuthenticateUserAsync
(userTextBox.Text, passwordTextBox.Text);
Log("Authentication started");
Guid?userId = await authTask;
Log("Authenticated - GUID={0}", userId);
if (userId == null)
{
Log("Authentication failure - abort.");
MessageBox.Show("User unknown, or incorrect password",
"Authentication failure",
MessageBoxButtons.OK, MessageBoxIcon.Error);
return;
}
Log("Fetching holdings");
List <StockHolding> holdings =
await portfolioService.GetPortfolioAsync(userId.Value);
Log("Received {0} holdings", holdings.Count);
Log("Fetching prices");
decimal totalWorth = await FetchPricesParallelAsync(holdings);
Log("Fetched all prices");
AddPortfolioEntry("TOTAL", null, null, totalWorth);
}
finally
{
fetchButton.Enabled = true;
}
}
private async Task <decimal> CalculateWorthAsyncImpl(string user, string password)
{
var userId = await authenticationService.AuthenticateUserAsync(user, password);
if (userId == null)
{
throw new AuthenticationException("Bad username or password");
}
var portfolio = await portfolioService.GetPortfolioAsync(userId.Value);
decimal total = 0m;
#if !PARALLEL
#region Serial implementation
foreach (var item in portfolio)
{
var price = await priceService.LookupPriceAsync(item.Ticker);
if (price != null)
{
total += price.Value * item.Quantity;
}
}
#endregion
#else
#region Parallel implementation
var tasks = portfolio.Select(async holding => new
{
holding,
price = await priceService.LookupPriceAsync(holding.Ticker)
}).ToList();
foreach (var task in tasks.InCompletionOrder())
{
var result = await task;
var holding = result.holding;
var price = result.price;
if (price != null)
{
total += holding.Quantity * price.Value;
}
}
#endregion
#endif
return(total);
}
