Xamarin Essentials FileSystem can you save async

Question

Looking into Xamarin essentials and wondering what the purpose of FileSystem is.

I was looking for something that would load and save a file for me async out of the box.

It looks to me and may be I am not understanding the usage that the only thing that it gives you is a location where to save and load the file and there is no functionality to actually save it for you eg "Old PCLStorage"

is this correct?

Answer 1

All Xamarin Essentials File System Helpers are doing is providing access to two different directories within your app, CacheDirectory and AppDataDirectory and access to the read-only pre-bundled files within application so you do not have to write platform-based code for these locations and do your own DI (or use Forms' DI) to access them...

Once you have the string-based directory location, then you use the normal .Net(Std) file and directory I/O routines. Create/delete subdirectories, create/read/write/delete a file using the async (or not) functions from the .Net(Std) framework or a third-party framework/package. Your choice...

CacheDirectory

The cache directory is a read/write location and it implements access to the "native" platform cache location. On Android this is the Cache

var cacheDir = FileSystem.CacheDirectory;

AppDataDirectory

The app data directory is the "default" location for where regular files should be stored.

As the docs state:

any files that are not user data file

FYI: This is not the place to be used for Sqlite databases and such if you are implementing/complying with platform dependent norms... Why Essentials did not include a database location is unknown to me when platforms like iOS and Android have APIs for them and formally documented locations... ;-/

Application bundled files (read-only)

OpenAppPackageFileAsync provides access (via a Stream) to read-only bundled files in your application (AndroidAssets, BundleResource, etc..)

using (var stream = await FileSystem.OpenAppPackageFileAsync("sushiLogo.png"))
{
    using (var reader = new StreamReader(stream))
    {
        var fileContents = await reader.ReadToEndAsync();
    }
}