[C] Dispose the Disposable (#7020)

Dispose the disposable readers while parsing StyleSheets

- fixes #6986

diff --git a/Xamarin.Forms.Core/StyleSheets/StyleSheet.cs b/Xamarin.Forms.Core/StyleSheets/StyleSheet.cs
index 34f875a..0c79855 100644 (file)
--- a/Xamarin.Forms.Core/StyleSheets/StyleSheet.cs
+++ b/Xamarin.Forms.Core/StyleSheets/StyleSheet.cs
@@ -36,7 +36,9 @@ namespace Xamarin.Forms.StyleSheets
                {
                        var styleSheet = new StyleSheet();
                        var resString = DependencyService.Get<IResourcesLoader>().GetResource(resourcePath, assembly, styleSheet, lineInfo);
-                       Parse(styleSheet, new CssReader(new StringReader(resString)));
+                       using (var textReader = new StringReader(resString))
+                       using (var cssReader = new CssReader(textReader))
+                               Parse(styleSheet, cssReader);
                        return styleSheet;
                }
 
@@ -56,7 +58,8 @@ namespace Xamarin.Forms.StyleSheets
                                throw new ArgumentNullException(nameof(reader));
 
                        var sheet = new StyleSheet();
-                       Parse(sheet, new CssReader(reader));
+                       using (var cssReader = new CssReader(reader))
+                               Parse(sheet, cssReader);
                        return sheet;
                }
 
@@ -94,13 +97,11 @@ namespace Xamarin.Forms.StyleSheets
                        }
                }
 
-               Type IStyle.TargetType
-                       => typeof(VisualElement);
+               Type IStyle.TargetType => typeof(VisualElement);
 
                void IStyle.Apply(BindableObject bindable)
                {
-                       var styleable = bindable as Element;
-                       if (styleable == null)
+                       if (!(bindable is Element styleable))
                                return;
                        Apply(styleable);
                }
@@ -114,8 +115,7 @@ namespace Xamarin.Forms.StyleSheets
 
                void ApplyCore(Element styleable)
                {
-                       var visualStylable = styleable as VisualElement;
-                       if (visualStylable == null)
+                       if (!(styleable is VisualElement visualStylable))
                                return;
                        foreach (var kvp in Styles) {
                                var selector = kvp.Key;
@@ -126,9 +126,6 @@ namespace Xamarin.Forms.StyleSheets
                        }
                }
 
-               void IStyle.UnApply(BindableObject bindable)
-               {
-                       throw new NotImplementedException();
-               }
+               void IStyle.UnApply(BindableObject bindable) => throw new NotImplementedException();
        }
 }