Rework database loading/migration

Application/Options/CategoryWindow.xaml.cs

@@ -29,7 +29,7 @@ namespace FeedCenter.Options
 
         private void HandleOkayButtonClick(object sender, RoutedEventArgs e)
         {
-            if (!this.Validate())
+            if (!this.IsValid())
                 return;
 
             // Dialog is good

Application/Options/GeneralOptionsPanel.xaml.cs

@@ -54,8 +54,6 @@ namespace FeedCenter.Options
 
             var expressions = this.GetBindingExpressions(new[] { UpdateSourceTrigger.Explicit });
             this.UpdateAllSources(expressions);
-
-            this.Validate();
         }
 
         public override string CategoryName => Properties.Resources.optionCategoryGeneral;
@@ -106,22 +104,22 @@ namespace FeedCenter.Options
         {
             var userAgents = new List<UserAgentItem>
             {
-                new UserAgentItem
+                new()
                 {
                     Caption = Properties.Resources.DefaultUserAgentCaption,
                     UserAgent = string.Empty
                 },
-                new UserAgentItem
+                new()
                 {
                     Caption = "Windows RSS Platform 2.0",
                     UserAgent = "Windows-RSS-Platform/2.0 (MSIE 9.0; Windows NT 6.1)"
                 },
-                new UserAgentItem
+                new()
                 {
                     Caption = "Feedly 1.0",
                     UserAgent = "Feedly/1.0"
                 },
-                new UserAgentItem
+                new()
                 {
                     Caption = "curl",
                     UserAgent = "curl/7.47.0"

Application/Options/OptionsWindow.xaml.cs

@@ -9,7 +9,7 @@ namespace FeedCenter.Options
     {
         #region Member variables
 
-        private readonly List<OptionsPanelBase> _optionPanels = new List<OptionsPanelBase>();
+        private readonly List<OptionsPanelBase> _optionPanels = new();
 
         private readonly FeedCenterEntities _database = Database.Entities;