/// <summary>
/// Add a trip to the persistent trip store, and saves the trips data file.
/// </summary>
/// <param name="trip">The trip to save or update in the data file.</param>
public async Task SaveTrip(Trip trip)
{
if (!Trips.Contains(trip))
{
Trips.Add(trip);
}
await WriteTrips();
}
/// <summary>
/// Load trips from a file on first-launch of the app. If the file does not yet exist,
/// pre-seed it with several trips, in order to give the app demonstration data.
/// </summary>
public async Task LoadTrips()
{
// Ensure that we don't load trip data more than once.
if (loaded)
{
return;
}
loaded = true;
StorageFolder folder = Windows.Storage.ApplicationData.Current.LocalFolder;
this.trips.Clear();
var item = await folder.TryGetItemAsync("trips.xml");
if (item == null)
{
// Add some 'starter' trips
trips.Add(
new Trip()
{
Destination = "London",
Description = "Trip to London!",
StartDate = new DateTime(2015, 5, 5),
EndDate = new DateTime(2015, 5, 15)
});
trips.Add(
new Trip()
{
Destination = "Melbourne",
Description = "Trip to Australia",
StartDate = new DateTime(2016, 2, 2),
EndDate = new DateTime(2016, 5, 17),
Notes = "Bring Sunscreen!"
});
trips.Add(
new Trip()
{
Destination = "Yosemite National Park",
Description = "Trip to Yosemite",
StartDate = new DateTime(2015, 7, 11),
EndDate = new DateTime(2015, 7, 19),
Notes = "Buy some new hiking boots"
});
await WriteTrips();
return;
}
// Load trips out of a simple XML format. For the purposes of this example, we're treating
// parse failures as "no trips exist" which will result in the file being erased.
if (item.IsOfType(StorageItemTypes.File))
{
StorageFile tripsFile = item as StorageFile;
string tripXmlText = await FileIO.ReadTextAsync(tripsFile);
try
{
XElement xmldoc = XElement.Parse(tripXmlText);
var tripElements = xmldoc.Descendants("Trip");
foreach (var tripElement in tripElements)
{
Trip trip = new Trip();
var destElement = tripElement.Descendants("Destination").FirstOrDefault();
if (destElement != null)
{
trip.Destination = destElement.Value;
}
var descElement = tripElement.Descendants("Description").FirstOrDefault();
if (descElement != null)
{
trip.Description = descElement.Value;
}
var startElement = tripElement.Descendants("StartDate").FirstOrDefault();
if (startElement != null)
{
DateTime startDate;
if (DateTime.TryParse(startElement.Value, CultureInfo.InvariantCulture, DateTimeStyles.AssumeLocal, out startDate))
{
trip.StartDate = startDate;
}
else
{
trip.StartDate = null;
}
}
var endElement = tripElement.Descendants("EndDate").FirstOrDefault();
if (endElement != null)
{
DateTime endDate;
if (DateTime.TryParse(endElement.Value, CultureInfo.InvariantCulture, DateTimeStyles.AssumeLocal, out endDate))
{
trip.EndDate = endDate;
}
else
{
trip.EndDate = null;
}
}
var notesElement = tripElement.Descendants("Notes").FirstOrDefault();
if (notesElement != null)
{
trip.Notes = notesElement.Value;
}
Trips.Add(trip);
}
}
catch (XmlException ex)
{
System.Diagnostics.Debug.WriteLine(ex.ToString());
return;
}
}
}
/// <summary>
/// Sets up the view model to create a new trip.
/// </summary>
internal void NewTrip()
{
showDelete = false;
Trip = new Trip();
}
/// <summary>
/// Delete a trip from the persistent trip store, and save the trips file.
/// </summary>
/// <param name="trip">The trip to delete. If the trip is not an existing trip in the store,
/// will not have an effect.</param>
public async Task DeleteTrip(Trip trip)
{
Trips.Remove(trip);
await WriteTrips();
}
/// <summary>
/// Sets up the view model to show an existing trip.
/// </summary>
/// <param name="trip"></param>
internal void ShowTrip(Trip trip)
{
showDelete = true;
Trip = trip;
}
/// <summary>
/// Construct Trip ViewModel, providing the store to persist trips.
/// Creates the RelayCommands to be bound to various buttons in the UI.
/// </summary>
/// <param name="store">The persistent store</param>
public TripViewModel(TripStore store)
{
trip = new Trip();
saveTripCommand = new RelayCommand(new Action(SaveTrip));
deleteTripCommand = new RelayCommand(new Action(DeleteTrip));
this.store = store;
}
/// <summary>
/// Load trips from a file on first-launch of the app. If the file does not yet exist,
/// pre-seed it with several trips, in order to give the app demonstration data.
/// </summary>
public async Task LoadTrips()
{
StorageFolder folder = Windows.Storage.ApplicationData.Current.LocalFolder;
this.trips.Clear();
IStorageItem item = null;
if (Windows.Globalization.ApplicationLanguages.PrimaryLanguageOverride != "zh-Hans-CN")
{
item = await folder.TryGetItemAsync("trips_en.xml");
if (item == null)
{
// Add some 'starter' trips
trips.Add(
new Trip()
{
Destination = "London",
Description = "Trip to London!",
StartDate = new DateTime(2015, 5, 5),
EndDate = new DateTime(2015, 5, 15)
});
trips.Add(
new Trip()
{
Destination = "Melbourne",
Description = "Trip to Australia",
StartDate = new DateTime(2016, 2, 2),
EndDate = new DateTime(2016, 5, 17),
Notes = "Bring Sunscreen!"
});
trips.Add(
new Trip()
{
Destination = "Las Vegas",
Description = "Trip to Las Vegas",
StartDate = new DateTime(2015, 7, 11),
EndDate = new DateTime(2015, 7, 19),
Notes = "Buy some new hiking boots"
});
await WriteTrips();
return;
}
}
else
{
item = await folder.TryGetItemAsync("trips_zh.xml");
if (item == null)
{
// Add some 'starter' trips
trips.Add(
new Trip()
{
Destination = "伦敦",
Description = "伦敦之旅!",
StartDate = new DateTime(2015, 5, 5),
EndDate = new DateTime(2015, 5, 15)
});
trips.Add(
new Trip()
{
Destination = "墨尔本",
Description = "澳大利亚之旅",
StartDate = new DateTime(2016, 2, 2),
EndDate = new DateTime(2016, 5, 17),
Notes = "带防晒霜!"
});
trips.Add(
new Trip()
{
Destination = "拉斯维加斯",
Description = "拉斯维加斯之旅",
StartDate = new DateTime(2015, 7, 11),
EndDate = new DateTime(2015, 7, 19),
Notes = "买一些新的登山靴"
});
await WriteTrips();
return;
}
}
// Load trips out of a simple XML format. For the purposes of this example, we're treating
// parse failures as "no trips exist" which will result in the file being erased.
if (item.IsOfType(StorageItemTypes.File))
{
StorageFile tripsFile = item as StorageFile;
string tripXmlText = await FileIO.ReadTextAsync(tripsFile);
try
{
XElement xmldoc = XElement.Parse(tripXmlText);
var tripElements = xmldoc.Descendants("Trip");
foreach (var tripElement in tripElements)
{
Trip trip = new Trip();
var destElement = tripElement.Descendants("Destination").FirstOrDefault();
if (destElement != null)
{
trip.Destination = destElement.Value;
}
var descElement = tripElement.Descendants("Description").FirstOrDefault();
if (descElement != null)
{
trip.Description = descElement.Value;
}
var startElement = tripElement.Descendants("StartDate").FirstOrDefault();
if (startElement != null)
{
DateTime startDate;
if (DateTime.TryParse(startElement.Value, out startDate))
{
trip.StartDate = startDate;
}
else
{
trip.StartDate = null;
}
}
var endElement = tripElement.Descendants("EndDate").FirstOrDefault();
if (endElement != null)
{
DateTime endDate;
if (DateTime.TryParse(startElement.Value, out endDate))
{
trip.EndDate = endDate;
}
else
{
trip.EndDate = null;
}
}
var notesElement = tripElement.Descendants("Notes").FirstOrDefault();
if (notesElement != null)
{
trip.Notes = notesElement.Value;
}
Trips.Add(trip);
}
}
catch (XmlException ex)
{
System.Diagnostics.Debug.WriteLine(ex.ToString());
return;
}
}
}
/// <summary>
/// Load trips from a file on first-launch of the app. If the file does not yet exist,
/// pre-seed it with several trips, in order to give the app demonstration data.
/// </summary>
public async Task LoadTrips()
{
StorageFolder folder = Windows.Storage.ApplicationData.Current.LocalFolder;
this.trips.Clear();
var item = await folder.TryGetItemAsync("trips.xml");
if (item == null)
{
// Add some 'starter' trips
trips.Add(
new Trip()
{
Destination = "London",
Description = "Trip to London!",
StartDate = new DateTime(2015, 5, 5),
EndDate = new DateTime(2015, 5, 15)
});
trips.Add(
new Trip()
{
Destination = "Melbourne",
Description = "Trip to Australia",
StartDate = new DateTime(2016, 2, 2),
EndDate = new DateTime(2016, 5, 17),
Notes = "Bring Sunscreen!"
});
trips.Add(
new Trip()
{
Destination = "Yosemite National Park",
Description = "Trip to Yosemite",
StartDate = new DateTime(2015, 7, 11),
EndDate = new DateTime(2015, 7, 19),
Notes = "Buy some new hiking boots"
});
await WriteTrips();
return;
}
// Load trips out of a simple XML format. For the purposes of this example, we're treating
// parse failures as "no trips exist" which will result in the file being erased.
if (item.IsOfType(StorageItemTypes.File))
{
StorageFile tripsFile = item as StorageFile;
string tripXmlText = await FileIO.ReadTextAsync(tripsFile);
try
{
XElement xmldoc = XElement.Parse(tripXmlText);
var tripElements = xmldoc.Descendants("Trip");
foreach (var tripElement in tripElements)
{
Trip trip = new Trip();
var destElement = tripElement.Descendants("Destination").FirstOrDefault();
if (destElement != null)
{
trip.Destination = destElement.Value;
}
var descElement = tripElement.Descendants("Description").FirstOrDefault();
if (descElement != null)
{
trip.Description = descElement.Value;
}
var startElement = tripElement.Descendants("StartDate").FirstOrDefault();
if (startElement != null)
{
DateTime startDate;
if (DateTime.TryParse(startElement.Value, CultureInfo.InvariantCulture, DateTimeStyles.AssumeUniversal, out startDate))
{
trip.StartDate = startDate;
}
else
{
trip.StartDate = null;
}
}
var endElement = tripElement.Descendants("EndDate").FirstOrDefault();
if (endElement != null)
{
DateTime endDate;
if (DateTime.TryParse(endElement.Value, CultureInfo.InvariantCulture, DateTimeStyles.AssumeUniversal, out endDate))
{
trip.EndDate = endDate;
}
else
{
trip.EndDate = null;
}
}
var notesElement = tripElement.Descendants("Notes").FirstOrDefault();
if (notesElement != null)
{
trip.Notes = notesElement.Value;
}
Trips.Add(trip);
}
}
catch (XmlException ex)
{
System.Diagnostics.Debug.WriteLine(ex.ToString());
return;
}
}
}
/// <summary>
/// Delete a trip from the persistent trip store, and save the trips file.
/// </summary>
/// <param name="trip">The trip to delete. If the trip is not an existing trip in the store,
/// will not have an effect.</param>
public async Task DeleteTrip(Trip trip)
{
Trips.Remove(trip);
await WriteTrips();
}