ItemDatabaseBasic.cs

using SQLite;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

using Xamarin.Forms;

namespace SQLiteNetPCLVS
{
    public class ItemDatabaseBasic
    {
        protected static object locker = new object();
        protected static SQLiteConnection database;

        public ItemDatabaseBasic()
        {
            database = DependencyService.Get<IDatabase>().DBConnect();
            database.CreateTable<Item>();
        }

        public IEnumerable<Item> GetItems ()
        {
            lock (locker)
            {
                return (from i in database.Table<Item>() select i).ToList();
            }
        }

        public IEnumerable<Item> GetFirstItems()
        {
            lock (locker)
            {
                return (from i in database.Query<Item>("SELECT * FROM Item WHERE Name = 'First'"));
            }
        }

        public Item GetItem(int id)
        {
            lock (locker)
            {
                return database.Table<Item>().FirstOrDefault(x => x.ID == id);
            }
        }

        public int SaveItem(Item item)
        {
            lock (locker)
            {
                if (item.ID != 0)
                {
                    database.Update(item);
                    return item.ID;
                } else
                {
                    return database.Insert(item);
                }
            }
        }

        public int DeleteItem(int id)
        {
            lock (locker)
            {
                return database.Delete<Item>(id);
            }
        }

        public void DeleteAllItems()
        {
            lock (locker)
            {
                database.DropTable<Item>();
                database.CreateTable<Item>();
            }
        }
    }
}