More null checks

Avalonia.sln.DotSettings

@@ -1,4 +1,5 @@
 <wpf:ResourceDictionary xml:space="preserve" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:s="clr-namespace:System;assembly=mscorlib" xmlns:ss="urn:shemas-jetbrains-com:settings-storage-xaml" xmlns:wpf="http://schemas.microsoft.com/winfx/2006/xaml/presentation">
+	<s:String x:Key="/Default/CodeInspection/ExcludedFiles/FilesAndFoldersToSkip2/=3E53A01A_002DB331_002D47F3_002DB828_002D4A5717E77A24_002Fd_003Aglass/@EntryIndexedValue">ExplicitlyExcluded</s:String>
 	<s:String x:Key="/Default/CodeInspection/ExcludedFiles/FilesAndFoldersToSkip2/=6417B24E_002D49C2_002D4985_002D8DB2_002D3AB9D898EC91/@EntryIndexedValue">ExplicitlyExcluded</s:String>
 	<s:String x:Key="/Default/CodeInspection/ExcludedFiles/FilesAndFoldersToSkip2/=E3A1060B_002D50D0_002D44E8_002D88B6_002DF44EF2E5BD72_002Ff_003Ahtml_002Ehtm/@EntryIndexedValue">ExplicitlyExcluded</s:String>
 	<s:String x:Key="/Default/CodeInspection/Highlighting/InspectionSeverities/=RedundantUsingDirective/@EntryIndexedValue">HINT</s:String>

src/Avalonia.Base/AvaloniaObject.cs

@@ -622,14 +622,9 @@ namespace Avalonia
         /// <returns>The default value.</returns>
         private object GetDefaultValue(AvaloniaProperty property)
         {
-            if (property.Inherits && _inheritanceParent != null)
-            {
-                return (_inheritanceParent as AvaloniaObject).GetValueInternal(property);
-            }
-            else
-            {
-                return ((IStyledPropertyAccessor)property).GetDefaultValue(GetType());
-            }
+            if (property.Inherits && _inheritanceParent is AvaloniaObject aobj)
+                return aobj.GetValueInternal(property);
+            return ((IStyledPropertyAccessor) property).GetDefaultValue(GetType());
         }
 
         /// <summary>

src/Avalonia.Base/Collections/AvaloniaDictionary.cs

@@ -103,11 +103,9 @@ namespace Avalonia.Collections
 
             _inner = new Dictionary<TKey, TValue>();
 
-            if (PropertyChanged != null)
-            {
-                PropertyChanged(this, new PropertyChangedEventArgs("Count"));
-                PropertyChanged(this, new PropertyChangedEventArgs($"Item[]"));
-            }
+            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs("Count"));
+            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs($"Item[]"));
+            
 
             if (CollectionChanged != null)
             {
@@ -144,12 +142,9 @@ namespace Avalonia.Collections
 
             if (_inner.TryGetValue(key, out value))
             {
-                if (PropertyChanged != null)
-                {
-                    PropertyChanged(this, new PropertyChangedEventArgs("Count"));
-                    PropertyChanged(this, new PropertyChangedEventArgs($"Item[{key}]"));
-                }
-
+                PropertyChanged?.Invoke(this, new PropertyChangedEventArgs("Count"));
+                PropertyChanged?.Invoke(this, new PropertyChangedEventArgs($"Item[{key}]"));
+                
                 if (CollectionChanged != null)
                 {
                     var e = new NotifyCollectionChangedEventArgs(
@@ -199,11 +194,9 @@ namespace Avalonia.Collections
 
         private void NotifyAdd(TKey key, TValue value)
         {
-            if (PropertyChanged != null)
-            {
-                PropertyChanged(this, new PropertyChangedEventArgs("Count"));
-                PropertyChanged(this, new PropertyChangedEventArgs($"Item[{key}]"));
-            }
+            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs("Count"));
+            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs($"Item[{key}]"));
+            
 
             if (CollectionChanged != null)
             {

src/Avalonia.Base/PriorityValue.cs

@@ -285,7 +285,7 @@ namespace Avalonia
                     Property.Name, 
                     _valueType, 
                     value,
-                    value.GetType());
+                    value?.GetType());
             }
         }
     }

src/Avalonia.Controls/Button.cs

@@ -275,7 +275,7 @@ namespace Avalonia.Controls
         {
             var button = e.Sender as Button;
             var isDefault = (bool)e.NewValue;
-            var inputRoot = button.VisualRoot as IInputElement;
+            var inputRoot = button?.VisualRoot as IInputElement;
 
             if (inputRoot != null)
             {

src/Avalonia.Controls/Control.cs

@@ -645,7 +645,7 @@ namespace Avalonia.Controls
 
             if (_focusAdorner != null)
             {
-                var adornerLayer = _focusAdorner.Parent as Panel;
+                var adornerLayer = (Panel)_focusAdorner.Parent;
                 adornerLayer.Children.Remove(_focusAdorner);
                 _focusAdorner = null;
             }

src/Avalonia.Controls/ItemsControl.cs

@@ -354,7 +354,7 @@ namespace Avalonia.Controls
             }
 
             var collection = sender as ICollection;
-            PseudoClasses.Set(":empty", collection.Count == 0);
+            PseudoClasses.Set(":empty", collection == null || collection.Count == 0);
         }
 
         /// <summary>

src/Avalonia.Controls/TextBox.cs

@@ -720,7 +720,7 @@ namespace Avalonia.Controls
                         if (pos < text.Length)
                         {
                             --pos;
-                            if (pos > 0 && Text[pos - 1] == '\r' && Text[pos] == '\n')
+                            if (pos > 0 && text[pos - 1] == '\r' && text[pos] == '\n')
                             {
                                 --pos;
                             }
@@ -771,6 +771,9 @@ namespace Avalonia.Controls
 
         private string GetSelection()
         {
+            var text = Text;
+            if (string.IsNullOrEmpty(text))
+                return "";
             var selectionStart = SelectionStart;
             var selectionEnd = SelectionEnd;
             var start = Math.Min(selectionStart, selectionEnd);
@@ -779,7 +782,7 @@ namespace Avalonia.Controls
             {
                 return "";
             }
-            return Text.Substring(start, end - start);
+            return text.Substring(start, end - start);
         }
 
         private int GetLine(int caretIndex, IList<FormattedTextLine> lines)

src/Avalonia.Controls/TopLevel.cs

@@ -106,7 +106,7 @@ namespace Avalonia.Controls
             _accessKeyHandler?.SetOwner(this);
             styler?.ApplyStyles(this);
 
-            ClientSize = PlatformImpl.ClientSize;
+            ClientSize = impl.ClientSize;
             
             this.GetObservable(PointerOverElementProperty)
                 .Select(

src/Avalonia.DotNetFrameworkRuntime/AppBuilder.cs

@@ -82,7 +82,13 @@ namespace Avalonia
 
         private void LoadAssembliesInDirectory()
         {
-            foreach (var file in new FileInfo(Assembly.GetEntryAssembly().Location).Directory.EnumerateFiles("*.dll"))
+            var location = Assembly.GetEntryAssembly().Location;
+            if(location == null)
+                return;
+            var dir = new FileInfo(location).Directory;
+            if (dir == null)
+                return;
+            foreach (var file in dir.EnumerateFiles("*.dll"))
             {
                 try
                 {

src/Avalonia.Styling/Controls/NameScope.cs

@@ -50,7 +50,7 @@ namespace Avalonia.Controls
                     return result;
                 }
 
-                visual = (visual as ILogical).LogicalParent as Visual;
+                visual = (visual as ILogical)?.LogicalParent as Visual;
             }
 
             return null;

src/Avalonia.Visuals/Rendering/ZIndexComparer.cs

@@ -8,6 +8,6 @@ namespace Avalonia.Rendering
     {
         public static readonly ZIndexComparer Instance = new ZIndexComparer();
 
-        public int Compare(IVisual x, IVisual y) => x.ZIndex.CompareTo(y.ZIndex);
+        public int Compare(IVisual x, IVisual y) => (x?.ZIndex ?? 0).CompareTo(y?.ZIndex ?? 0);
     }
 }

src/Gtk/Avalonia.Cairo/Media/DrawingContext.cs

@@ -9,6 +9,7 @@ using Avalonia.Cairo.Media.Imaging;
 using Avalonia.Media;
 using Avalonia.Platform;
 using Avalonia.Rendering;
+// ReSharper disable PossibleNullReferenceException
 
 namespace Avalonia.Cairo.Media
 {

src/Gtk/Avalonia.Gtk3/SystemDialogs.cs

@@ -28,6 +28,7 @@ namespace Avalonia.Gtk3
             List<IDisposable> disposables = null;
             Action dispose = () =>
             {
+                // ReSharper disable once PossibleNullReferenceException
                 foreach (var d in disposables)
                     d.Dispose();
                 disposables.Clear();

src/Markup/Avalonia.Markup.Xaml/Parsers/SelectorParser.cs

@@ -68,7 +68,7 @@ namespace Avalonia.Markup.Xaml.Parsers
                 }
                 else if (property != null)
                 {
-                    var type = result.TargetType;
+                    var type = result?.TargetType;
 
                     if (type == null)
                     {