/// <summary>Returns a file if it is found in the specified storage strategy</summary>
/// <param name="key">Path of the file in storage</param>
/// <param name="location">Location storage strategy</param>
/// <returns>StorageFile</returns>
private static async Task <Windows.Storage.StorageFile> GetIfFileExistsAsync(string key,
StorageStrategies location = StorageStrategies.Local,
Windows.Storage.CreationCollisionOption option = Windows.Storage.CreationCollisionOption.FailIfExists)
{
Windows.Storage.StorageFile retval;
try
{
switch (location)
{
case StorageStrategies.Local:
retval = await Windows.Storage.ApplicationData.Current.LocalFolder.GetFileAsync(key);
break;
case StorageStrategies.Roaming:
retval = await Windows.Storage.ApplicationData.Current.RoamingFolder.GetFileAsync(key);
break;
case StorageStrategies.Temporary:
retval = await Windows.Storage.ApplicationData.Current.TemporaryFolder.GetFileAsync(key);
break;
default:
throw new NotSupportedException(location.ToString());
}
}
catch (System.IO.FileNotFoundException)
{
return(null);
}
return(retval);
}
private static async Task <IRandomAccessStream> CreateFileIAStreamAsync(string key, StorageStrategies location = StorageStrategies.Local,
Windows.Storage.CreationCollisionOption option = Windows.Storage.CreationCollisionOption.OpenIfExists, FileAccessMode fileAccessMode = FileAccessMode.ReadWrite)
{
var _File = await CreateFileAsync(key, location, Windows.Storage.CreationCollisionOption.ReplaceExisting);
if (_File != null)
{
return(await _File.OpenAsync(fileAccessMode));
}
else
{
return(null);
}
}
/// <summary>Serializes an object and write to file in specified storage strategy</summary>
/// <typeparam name="T">Specified type of object to serialize</typeparam>
/// <param name="key">Path to the file in storage</param>
/// <param name="value">Instance of object to be serialized and written</param>
/// <param name="location">Location storage strategy</param>
public async Task <bool> WriteFileAsync <T>(string key, T value, StorageStrategies location = StorageStrategies.Local,
Windows.Storage.CreationCollisionOption option = Windows.Storage.CreationCollisionOption.ReplaceExisting)
{
// create file
var file = await CreateFileAsync(key, location, option);
// convert to string
var serializedValue = Serialize(value);
// save string to file
await FileIO.WriteTextAsync(file, serializedValue);
// result
return(await FileExistsAsync(key, location));
}
private static async Task <Windows.Storage.StorageFile> GetIfFileExistsAsync(string key, Windows.Storage.StorageFolder folder,
Windows.Storage.CreationCollisionOption option = Windows.Storage.CreationCollisionOption.FailIfExists)
{
Windows.Storage.StorageFile retval;
try
{
retval = await folder.GetFileAsync(key);
}
catch (System.IO.FileNotFoundException)
{
// System.Diagnostics.Debug.WriteLine("GetIfFileExistsAsync:FileNotFoundException");
return(null);
}
return(retval);
}
private static async Task <Windows.Storage.StorageFile> CreateFileAsync(string key, StorageStrategies location = StorageStrategies.Local,
Windows.Storage.CreationCollisionOption option = Windows.Storage.CreationCollisionOption.OpenIfExists)
{
switch (location)
{
case StorageStrategies.Local:
return(await Windows.Storage.ApplicationData.Current.LocalFolder.CreateFileAsync(key, option));
case StorageStrategies.Roaming:
return(await Windows.Storage.ApplicationData.Current.RoamingFolder.CreateFileAsync(key, option));
case StorageStrategies.Temporary:
return(await Windows.Storage.ApplicationData.Current.TemporaryFolder.CreateFileAsync(key, option));
default:
throw new NotSupportedException(location.ToString());
}
}
public async Task <StorageFile> SaveToFile(WriteableBitmap image, string file_name, Windows.Storage.CreationCollisionOption collision, BitmapPixelFormat image_format, BitmapAlphaMode alpha_mode)
{
var file = await KnownFolders.PicturesLibrary.CreateFileAsync(file_name, collision);
using (IRandomAccessStream image_stream = await file.OpenAsync(FileAccessMode.ReadWrite))
{
BitmapEncoder encoder = await BitmapEncoder.CreateAsync(BitmapEncoder.BmpEncoderId, image_stream);
Stream pixel_stream = image.PixelBuffer.AsStream();
byte[] pixel_array = new byte[pixel_stream.Length];
await pixel_stream.ReadAsync(pixel_array, 0, pixel_array.Length);
encoder.SetPixelData(image_format, alpha_mode,
(uint)image.PixelWidth,
(uint)image.PixelHeight,
96.0,
96.0,
pixel_array);
await encoder.FlushAsync();
}
return(file);
}
