private async Task <MainViewModel> PreloadServiceData()
{
TaskScheduler uiTaskSheduler = TaskScheduler.FromCurrentSynchronizationContext();
MainViewModel vm = null;
Exception exception = null;
try
{
vm = new MainViewModel(true);
var loadTrends = TwitterHelper.GetTrendsAsync()
.ContinueWith(loadTask =>
{
if (exception != null)
{
return;
}
exception = loadTask.Exception;
if (exception != null)
{
return;
}
try
{
var trendsCollection = loadTask.Result
.Where(trend => trend.Name.StartsWith("#"))
.Take <TwitterTrendViewModel>(10);
using (var db = new TwitterContext())
{
foreach (var t in trendsCollection)
{
if (db.Trends.Any(tt => tt.TrendName == t.Name))
{
continue;
}
db.Trends.Add(new TwitterTrend
{
TrendName = t.Name
});
db.SaveChanges();
}
}
}
catch (Exception ex)
{
exception = ex;
}
});
var loadTweets = vm.LoadPostsAsync(uiTaskSheduler);
#if X
TwitterHelper.GetTweetsAsync(40, null)// 1200112449287905280 - 1) // null)
.ContinueWith(loadTask =>
{
if (exception != null)
{
return;
}
exception = loadTask.Exception;
if (exception != null)
{
return;
}
try
{
var tweetsCollection = loadTask.Result;//.Take(10);
using (var db = new TwitterContext())
{
using (var transaction = db.Database.BeginTransaction())
{
try
{
var users = db.Users.ToDictionary(u => u.UserName);
foreach (var tw in tweetsCollection)
{
if (vm.PostMinId == null || vm.PostMinId.Value > tw.Id)
{
vm.PostMinId = tw.Id;
}
TwitterUser user;
if (!users.TryGetValue(tw.User.UserName, out user))
{
user = new TwitterUser()
{
UserName = tw.User.UserName,
UserScreenName = tw.User.UserScreenName,
FavouritesCount = tw.User.FavouritesCount,
FollowersCount = tw.User.FollowersCount,
FriendsCount = tw.User.FriendsCount,
Description = tw.User.Description,
ProfileImageUrl = tw.User.ProfileImageUrl
};
users.Add(tw.User.UserName, user);
db.Users.Add(user);
}
user.Posts.Add(
new TwitterPost
{
TwitterId = tw.Id,
Text = tw.Text,
CreatedDate = tw.CreatedDate,
RetweetCount = tw.RetweetCount
});
}
db.SaveChanges();
transaction.Commit();
}
catch
{
transaction.Rollback();
throw;
}
}
}
}
catch (Exception ex)
{
exception = ex;
}
}, uiTaskSheduler);
#endif
var loadUserInfo = TwitterHelper.GetUserInfoAsync()
.ContinueWith(loadTask =>
{
if (exception != null)
{
return;
}
exception = loadTask.Exception;
if (exception != null)
{
return;
}
try
{
var userInfo = loadTask.Result;
if (userInfo != null)
{
vm.User = userInfo;
}
}
catch (Exception ex)
{
exception = ex;
}
});
await Task.WhenAll(loadTrends, loadTweets, loadUserInfo); // три задачи в параллель!!!
}
catch (Exception ex)
{
exception = ex;
}
if (exception == null)
{
return(vm);
}
else
{
string error;
if (exception is TwitterException)
{
error = string.Format("Произошло специфическое исключение {0}:\n\t{1}", exception.GetType().Name, exception.Message);
}
else
{
error = string.Format("Произошло исключение {0}:\n\t{1}", exception.GetType().Name, exception.Message);
}
MessageBox.Show(error, "Ошибка", MessageBoxButton.OK, MessageBoxImage.Error);
this.Close();
}
return(null);
}