Xamarin.Forms SQLite.net data execution

Question

I have SQLite database generated in Sqlite Browser with imported Excel files. It has few tables. Each table has same structure.

Columns are:

• Age
• 2000m
• 2000f
• 2500m
• 2500f
• ... etc.

All I need is to open this database in my Xamarin.Forms Shared project and execute 1 item per time.

Each cell includes 1 double number. I need to execute this number and send it to Label on screen.

I don't need to write anything to this database. Only read.

Best way I can imagine is to Execute SQL like:

Select 2000m From Bravo Where Age = 20.

Can someone help me with that?

Answer 1

So the problem was with Windows Phone. Somehow it can't start SQLiteConnection. But Android does, so iOS must too.

First of all i moved my DB to local path of application:

 public static string GetLocalFilePath(string filename)
        {
            string path = System.Environment.GetFolderPath(System.Environment.SpecialFolder.Personal);
            string dbPath = Path.Combine(path, filename);

            CopyDatabaseIfNotExists(dbPath);

            return dbPath;
        }

        private static void CopyDatabaseIfNotExists(string dbPath)
        {
            if (!File.Exists(dbPath))
            {
                using (var br = new BinaryReader(Application.Context.Assets.Open("KDLife_mobileDB.db3")))
                {
                    using (var bw = new BinaryWriter(new FileStream(dbPath, FileMode.Create)))
                    {
                        byte[] buffer = new byte[2048];
                        int length = 0;
                        while ((length = br.Read(buffer, 0, buffer.Length)) > 0)
                        {
                            bw.Write(buffer, 0, length);
                        }
                    }
                }
            }
        }

        protected override void OnCreate (Bundle bundle)
        {
            base.OnCreate (bundle);

            global::Xamarin.Forms.Forms.Init (this, bundle);
            global::Xamarin.FormsMaps.Init(this, bundle);

            string dbPath = GetLocalFilePath("KDLife_mobileDB.db3");

            LoadApplication (new KDLife_mobile.App ());

            App.ScreenWidth = (int)Resources.DisplayMetrics.WidthPixels;
            App.ScreenHeight = (int)Resources.DisplayMetrics.HeightPixels;


        }

Then i opened connection:

public SQLiteConnection DBClass_conn()
        {
            database = new SQLiteConnection (DatabasePath);
            return database;
        }

Then i added SQLiteCommand:

SQLiteCommand cmd = new SQLiteCommand(App.Database.DBClass_conn());

And query:

public string querytext(string q_table)
        {
            string sql = "SELECT \"2000f\" FROM Bravo WHERE Age = \"20\" AND Period = \"15\"";//, App.amount_gender, q_table, App.age;
            return sql;
        }

Then i just change CommandText and ExecuteScalar:

cmd.CommandText = querytext("Symphony");
string count = (string)cmd.ExecuteScalar<string>();

Right now it execute only 1 query, but it's not hard to make it more universal.