CODEWITHSUNDEEP
c#xamarinxamarin.forms
Federico Navarrete
Federico Navarrete

Reputation: 3274

How to copy a local DB in Xamarin.Forms?

I created a project where I'm trying to copy to local files in Xamarin.Forms, one is an XML and one is a local DB in SQLite:

preview

I configured them as EmbeddedResources. I tried to access their current location using this:

public static class Constants
{
        public const string DatabaseFilename = "savethatpower.db";

        public const SQLite.SQLiteOpenFlags Flags =
            // open the database in read/write mode
            SQLite.SQLiteOpenFlags.ReadWrite |
            // create the database if it doesn't exist
            SQLite.SQLiteOpenFlags.Create |
            // enable multi-threaded database access
            SQLite.SQLiteOpenFlags.SharedCache;

        public static string DatabasePath
        {
            get
            {
                var basePath = Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData);
                return Path.Combine(basePath, DatabaseFilename);
            }
        }
}

public void CopyFiles(string name) {

    var localPath = $"{Application.Current.Resources.Source.AbsolutePath}/{name}";

    File.Copy(localPath, Constants.DatabasePath);
}

CopyFiles("savethatpower.db");
CopyFiles("dbInfo.xml");

This line provides me a tricky bug since the beginning: var localPath = $"{Application.Current.Resources.Source.AbsolutePath}/{name}";

InnerException {System.NullReferenceException: Object reference not set to an instance of an object at SaveThatPower.Classes.XML.XML2CSharp..ctor (System.String name) [0x00008] in /Users/fanmixco/Documents/GitHub/SaveThatPower/SaveThatPower/SaveThatPower/Classes/XML/XML2CSh…} System.NullReferenceException

I found that the Source is null but I don't know how to access its current location. I also tried directly accessing the files like this:

    File.Copy("dbVersion.xml", Constants.DatabasePath);

But nothing happened. I'm wondering, do you know what is the correct way to copy files? Thanks.

Upvotes: 0

Views: 186

Answers (1)

Cheesebaron
Cheesebaron

Reputation: 24470

Files marked as EmbeddedResource will be accessible through the Assembly. You will need to do something like:

var assembly = this.GetType().Assembly;
using var databaseStream = assembly.GetManifestResourceStream("My.Assembly.Namespace.my_database_file.db");
using var fileStream = File.Open(localPath, FileMode.CreateNew);
await databaseStream.CopyToAsync(fileStream);

Upvotes: 1

Related Questions