Resolving warnings and treating warnings as errors in WinUI project. (#824)

Wino.Mail.WinUI/Helpers/CalendarXamlHelpers.cs

@@ -15,7 +15,7 @@ namespace Wino.Calendar.Helpers;
 public static class CalendarXamlHelpers
 {
     public static CalendarItemViewModel GetFirstAllDayEvent(CalendarEventCollection collection)
-        => (CalendarItemViewModel)collection.AllDayEvents.FirstOrDefault();
+        => collection.AllDayEvents.OfType<CalendarItemViewModel>().FirstOrDefault()!;
 
     /// <summary>
     /// Returns full date + duration info in Event Details page details title.

Wino.Mail.WinUI/Helpers/WinoVisualTreeHelper.cs

@@ -6,18 +6,20 @@ namespace Wino.Helpers;
 
 public static class WinoVisualTreeHelper
 {
-    public static T GetChildObject<T>(DependencyObject obj, string name) where T : FrameworkElement
+    public static T? GetChildObject<T>(DependencyObject? obj, string name) where T : FrameworkElement
     {
-        DependencyObject child = null;
-        T grandChild = null;
+        if (obj == null) return null;
+
+        DependencyObject? child = null;
+        T? grandChild = null;
 
         for (int i = 0; i <= VisualTreeHelper.GetChildrenCount(obj) - 1; i++)
         {
             child = VisualTreeHelper.GetChild(obj, i);
 
-            if (child is T && (((T)child).Name == name | string.IsNullOrEmpty(name)))
+            if (child is T typedChild && (typedChild.Name == name || string.IsNullOrEmpty(name)))
             {
-                return (T)child;
+                return typedChild;
             }
             else
             {
@@ -31,7 +33,7 @@ public static class WinoVisualTreeHelper
         return null;
     }
 
-    public static IEnumerable<T> FindDescendants<T>(this DependencyObject depObj) where T : DependencyObject
+    public static IEnumerable<T> FindDescendants<T>(this DependencyObject? depObj) where T : DependencyObject
     {
         if (depObj != null)
         {

Wino.Mail.WinUI/Helpers/XamlHelpers.cs

@@ -51,7 +51,7 @@ public static class XamlHelpers
     public static ListViewSelectionMode BoolToSelectionMode(bool isSelectionMode) => isSelectionMode ? ListViewSelectionMode.Multiple : ListViewSelectionMode.None;
     public static string BoolToSelectionModeText(bool isSelectionMode) => isSelectionMode ? Translator.Buttons_Cancel : Translator.Buttons_Multiselect;
 
-    public static Microsoft.UI.Xaml.Media.Imaging.BitmapImage Base64ToBitmapImage(string base64String)
+    public static Microsoft.UI.Xaml.Media.Imaging.BitmapImage? Base64ToBitmapImage(string base64String)
     {
         if (string.IsNullOrEmpty(base64String))
             return null;
@@ -154,7 +154,7 @@ public static class XamlHelpers
         if (groupObject is string stringObject)
             return stringObject;
 
-        object dateObject = null;
+        object? dateObject = null;
 
         // From regular mail header template
         if (groupObject is DateTime groupedDate)
@@ -180,7 +180,7 @@ public static class XamlHelpers
 
             }
             else
-                return dateObject.ToString();
+                return dateObject.ToString() ?? string.Empty;
         }
 
         return Translator.UnknownDateHeader;
@@ -321,6 +321,10 @@ public static class XamlHelpers
         "xmlns='http://schemas.microsoft.com/winfx/2006/xaml/presentation'>" +
         "<Path.Data>" + pathMarkup + "</Path.Data></Path>";
         var path = XamlReader.Load(xaml) as Microsoft.UI.Xaml.Shapes.Path;
+        if (path?.Data == null)
+        {
+            return new PathGeometry();
+        }
 
         Geometry geometry = path.Data;
         path.Data = null;