switch to sqlite

Billing.Shared/Helper.cs

@@ -1,8 +1,11 @@
 using Billing.Models;
+using Billing.UI;
 using Billing.Views;
 using System;
 using System.Globalization;
 using System.Linq;
+using System.Runtime.CompilerServices;
+using System.Threading.Tasks;
 using Xamarin.Essentials;
 using Xamarin.Forms;
 
@@ -82,7 +85,7 @@ namespace Billing
         {
             return new UIBill(b)
             {
-                Icon = App.Categories.FirstOrDefault(c => c.Id == b.CategoryId)?.Icon ?? BaseModel.ICON_DEFAULT,
+                Icon = App.Categories.FirstOrDefault(c => c.Id == b.CategoryId)?.Icon ?? Definition.DefaultIcon,
                 Name = b.Name,
                 DateCreation = b.CreateTime,
                 Amount = b.Amount,
@@ -130,4 +133,24 @@ namespace Billing
 
         public delegate void PropertyValueChanged<TResult, TOwner>(TOwner obj, TResult old, TResult @new);
     }
+
+    internal class AsyncLazy<T>
+    {
+        private readonly Lazy<Task<T>> instance;
+
+        public AsyncLazy(Func<T> factory)
+        {
+            instance = new Lazy<Task<T>>(() => Task.Run(factory));
+        }
+
+        public AsyncLazy(Func<Task<T>> factory)
+        {
+            instance = new Lazy<Task<T>>(() => Task.Run(factory));
+        }
+
+        public TaskAwaiter<T> GetAwaiter()
+        {
+            return instance.Value.GetAwaiter();
+        }
+    }
 }