feat: PixelSize TryParse (#14979)

* feat: PixelSize TryParse

* test: Add PixelSize Parse and TryParse

* fix: Address review

* fix: Address Review

* fix: Address review

src/Avalonia.Base/PixelSize.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Diagnostics.CodeAnalysis;
 using System.Globalization;
 using Avalonia.Utilities;
 
@@ -67,13 +68,38 @@ namespace Avalonia
         /// </summary>
         /// <param name="s">The string.</param>
         /// <returns>The <see cref="PixelSize"/>.</returns>
+        /// <exception cref="FormatException"/>
         public static PixelSize Parse(string s)
         {
-            using (var tokenizer = new StringTokenizer(s, CultureInfo.InvariantCulture, exceptionMessage: "Invalid PixelSize."))
+            if (TryParse(s, out var result))
             {
-                return new PixelSize(
-                    tokenizer.ReadInt32(),
-                    tokenizer.ReadInt32());
+                return result;
+            }
+            throw new FormatException("Invalid PixelSize.");
+        }
+
+        /// <summary>
+        /// Try parsing <paramref name="source"/> as <see cref="PixelSize"/>.
+        /// </summary>
+        /// <param name="source">The <see cref="string"/> to parse.</param>
+        /// <param name="result">The result of parsing. if <paramref name="source"/> is not valid <paramref name="result"/> is <see cref="PixelSize.Empty"/> </param>
+        /// <returns><c>true</c> if <paramref name="source"/> is valid <see cref="PixelSize"/>, otherwise <c>false</c>.</returns>
+        public static bool TryParse([NotNullWhen(true)] string? source,
+            out PixelSize result)
+        {
+            result = Empty;
+            if(string.IsNullOrEmpty(source))
+            {
+                return false;
+            }
+            using (var tokenizer = new StringTokenizer(source, exceptionMessage: "Invalid PixelSize."))
+            {
+                if (tokenizer.TryReadInt32(out var w) && tokenizer.TryReadInt32(out var h))
+                {
+                    result = new(w, h);
+                    return true;
+                }
+                return false;
             }
         }
 

tests/Avalonia.Base.UnitTests/PixelSizeTests.cs

@@ -0,0 +1,77 @@
+using System;
+using System.Collections.Generic;
+using Xunit;
+
+namespace Avalonia.Base.UnitTests;
+
+public class PixelSizeTests
+{
+    [Theory]
+    [MemberData(nameof(ParseArguments))]
+    public void Parse(string source, PixelSize expected, Exception exception)
+    {
+        Exception error = null;
+        PixelSize result = default;
+        try
+        {
+            result = PixelSize.Parse(source);
+        }
+        catch (Exception ex)
+        {
+            error = ex;
+        }
+        Assert.Equal(exception?.Message, error?.Message);
+        Assert.Equal(expected, result);
+    }
+
+    [Theory]
+    [MemberData(nameof(TryParseArguments))]
+    public void TryParse(string source, PixelSize? expected, Exception exception)
+    {
+        Exception error = null;
+        PixelSize result = PixelSize.Empty;
+        try
+        {
+
+            PixelSize.TryParse(source, out result);
+        }
+        catch (Exception ex)
+        {
+            error = ex;
+        }
+        Assert.Equal(exception?.Message, error?.Message);
+        Assert.Equal(expected, result);
+    }
+
+    public static IEnumerable<object[]> ParseArguments()
+    {
+        yield return new object[]
+        {
+            "1024,768",
+            new PixelSize(1024, 768),
+            null,
+        };
+        yield return new object[]
+        {
+            "1024x768",
+            default(PixelSize),
+            new FormatException("Invalid PixelSize."),
+        };
+    }
+
+    public static IEnumerable<object[]> TryParseArguments()
+    {
+        yield return new object[]
+        {
+            "1024,768",
+            new PixelSize(1024, 768),
+            null,
+        };
+        yield return new object[]
+        {
+            "1024x768",
+            PixelSize.Empty,
+            null,
+        };
+    }
+}