Enable string search and comparison CA rules in Core

src/Core/src/.editorconfig

@@ -6,6 +6,7 @@
 dotnet_analyzer_diagnostic.category-Performance.severity = warning
 
 [*.cs]
+dotnet_diagnostic.CA1307.severity = error
 dotnet_diagnostic.CA1805.severity = error
 dotnet_diagnostic.CA1806.severity = error
 dotnet_diagnostic.CA1825.severity = error
@@ -15,3 +16,5 @@ dotnet_diagnostic.CA1846.severity = error
 dotnet_diagnostic.CA1847.severity = error
 dotnet_diagnostic.CA1859.severity = error
 dotnet_diagnostic.CA1860.severity = error
+dotnet_diagnostic.CA1865.severity = error
+dotnet_diagnostic.CA2249.severity = error

src/Core/src/Converters/CornerRadiusTypeConverter.cs

@@ -20,8 +20,8 @@ public override object ConvertFrom(ITypeDescriptorContext? context, CultureInfo?
 
 			if (strValue != null)
 			{
-				value = strValue.Trim();
-				if (strValue.IndexOf(",", StringComparison.Ordinal) != -1)
+				strValue = strValue.Trim();
+				if (strValue.ContainsChar(','))
 				{ //Xaml
 					var cornerRadius = strValue.Split(',');
 					if (cornerRadius.Length == 4
@@ -35,7 +35,7 @@ public override object ConvertFrom(ITypeDescriptorContext? context, CultureInfo?
 						&& double.TryParse(cornerRadius[0], NumberStyles.Number, CultureInfo.InvariantCulture, out double l))
 						return new CornerRadius(l);
 				}
-				else if (strValue.Trim().IndexOf(" ", StringComparison.Ordinal) != -1)
+				else if (strValue.ContainsChar(' '))
 				{ //CSS
 					var cornerRadius = strValue.Split(' ');
 					if (cornerRadius.Length == 2

src/Core/src/Converters/ThicknessTypeConverter.cs

@@ -24,7 +24,7 @@ public override object ConvertFrom(ITypeDescriptorContext context, CultureInfo c
 			{
 				strValue = strValue.Trim();
 
-				if (strValue.IndexOf(",", StringComparison.Ordinal) != -1)
+				if (strValue.ContainsChar(','))
 				{ //Xaml
 					var thickness = strValue.Split(',');
 					switch (thickness.Length)
@@ -43,7 +43,7 @@ public override object ConvertFrom(ITypeDescriptorContext context, CultureInfo c
 							break;
 					}
 				}
-				else if (strValue.IndexOf(" ", StringComparison.Ordinal) != -1)
+				else if (strValue.ContainsChar(' '))
 				{ //CSS
 					var thickness = strValue.Split(' ');
 					switch (thickness.Length)

src/Core/src/Extensions/StringExtensions.cs

@@ -0,0 +1,28 @@
+using System;
+
+namespace Microsoft.Maui
+{
+	/// <summary>
+	/// Convenience extensions so we have a single place to accommodate the fact we have to support .NET Standard 2.0
+	/// </summary>
+	internal static class StringExtensions
+	{
+		public static bool ContainsChar(this string toSearch, char character)
+		{
+#if NETSTANDARD2_0
+			return toSearch.Contains(character.ToString());
+#else
+			return toSearch.Contains(character, StringComparison.Ordinal);
+#endif
+		}
+
+		public static int IndexOfChar(this string toSearch, char character)
+		{
+#if NETSTANDARD2_0
+			return toSearch.IndexOf(character);
+#else
+			return toSearch.IndexOf(character, StringComparison.Ordinal);
+#endif
+		}
+	}
+}

src/Core/src/Fonts/FontFile.cs

@@ -63,7 +63,7 @@ public static FontFile FromString(string input)
 		{
 			_ = input ?? throw new ArgumentNullException(nameof(input));
 
-			var hashIndex = input.IndexOf("#", StringComparison.Ordinal);
+			var hashIndex = input.IndexOfChar('#');
 			//UWP names require Spaces. Sometimes people may use those, "CuteFont-Regular#Cute Font" should be "CuteFont-Regular#CuteFont"
 			var postScriptName = hashIndex > 0 ? input.Substring(hashIndex + 1)
 #if NETSTANDARD2_0
@@ -98,7 +98,7 @@ static IEnumerable<string> GetFontName(string fontFamily)
 		{
 			_ = fontFamily ?? throw new ArgumentNullException(nameof(fontFamily));
 
-			if (fontFamily.IndexOf(" ", StringComparison.Ordinal) != -1)
+			if (fontFamily.ContainsChar(' '))
 			{
 				yield return fontFamily;
 				//We are done, they have spaces, they have it handled.
@@ -107,7 +107,7 @@ static IEnumerable<string> GetFontName(string fontFamily)
 
 			string currentString = "";
 			char lastCharacter = ' ';
-			var index = fontFamily.LastIndexOf("-", StringComparison.Ordinal);
+			var index = fontFamily.LastIndexOf('-');
 			bool multipleCaps = false;
 			var cleansedString = index > 0 ? fontFamily.Substring(0, index) : fontFamily;
 			foreach (var c in cleansedString)

src/Core/src/Fonts/FontManager.Android.cs

@@ -195,7 +195,7 @@ string FontNameToFontFile(string fontFamily)
 		{
 			fontFamily ??= string.Empty;
 
-			int hashtagIndex = fontFamily.IndexOf("#", StringComparison.Ordinal);
+			int hashtagIndex = fontFamily.IndexOf('#', StringComparison.Ordinal);
 			if (hashtagIndex >= 0)
 				return fontFamily.Substring(0, hashtagIndex);
 

src/Core/src/Platform/iOS/TimePickerExtensions.cs

@@ -54,15 +54,15 @@ public static void UpdateTime(this MauiTimePicker mauiTimePicker, ITimePicker ti
 
 			if (format != null)
 			{
-				if (format.IndexOf("H", StringComparison.Ordinal) != -1)
+				if (format.Contains('H', StringComparison.Ordinal))
 				{
 					var ci = new CultureInfo("de-DE");
 					NSLocale locale = new NSLocale(ci.TwoLetterISOLanguageName);
 
 					if (picker != null)
 						picker.Locale = locale;
 				}
-				else if (format.IndexOf("h", StringComparison.Ordinal) != -1)
+				else if (format.Contains('h', StringComparison.Ordinal))
 				{
 					var ci = new CultureInfo("en-US");
 					NSLocale locale = new NSLocale(ci.TwoLetterISOLanguageName);