SpecialFolder。个人现有的sqlite数据库

Question

On my Xamarin android application i create db path using the "System.Environment.SpecialFolder.Personal". I have an existing sqlite database. Where in the project and with what properties must i include the database to be used in the peronal folder?

Answer 1

You can use Xamarin.Essentials to access your read-only bundle/asset resource and copy it without have to use native platform code or if you are coding within an Xamarin.Android project, you can directly use Android.Content 's Assets

So assuming you have a database in your Android Assets folder:

Assets
   db.sqlite

Xamarin Essentials / NetStd2.0 Code Example:

var copyToLocationPath = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Personal), "db.sqlite");
if (!File.Exists(copyToLocationPath))
{
    using (var assetStream = await Xamarin.Essentials.FileSystem.OpenAppPackageFileAsync("db.sqlite"))
    using (var fileStream = new FileStream(copyToLocationPath, FileMode.Create, FileAccess.Write))
    {
        await assetStream.CopyToAsync(fileStream);
    }
}
var connection = new SqliteConnection(copyToLocationPath);

Xamarin Android code sample (Directly use Assets ):

var copyToLocationPath = Path.Combine(System.Environment.GetFolderPath(System.Environment.SpecialFolder.Personal), "db.sqlite");
if (!File.Exists(copyToLocationPath))
{
    using (var assetStream = Assets.Open("db.sqlite"))
    using (var fileStream = new FileStream(copyToLocationPath, FileMode.Create, FileAccess.Write))
    {
         await assetStream.CopyToAsync(fileStream);
    }
}