feat: Implement ScrollItemAdapter AccessKeyStringBuilder

src/Uno.UI/DirectUI/AccessKeyStringBuilder.cs

@@ -0,0 +1,94 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License. See LICENSE in the project root for license information.
+// MUX Reference AccessKeyStringBuilder_Partial.cpp, tag winui3/release/1.5-stable
+
+using System;
+using Microsoft.UI.Xaml;
+using Microsoft.UI.Xaml.Automation.Peers;
+using Microsoft.UI.Xaml.Documents;
+
+namespace Uno.UI.DirectUI;
+
+internal class AccessKeyStringBuilder
+{
+	static void InterleaveStringWithDelimiters(string toInterleave, int length, out string interleavedString)
+	{
+		if (length > 3)
+		{
+			throw new ArgumentOutOfRangeException(nameof(length), "Length must be at most 3");
+		}
+
+		// We take advantage of the fact that access keys can be at most 3 characters long.
+		// So, after interleaving ',' and ' ', the string can be at most 9 characters long.
+		var accessKeyInterleaved = new char[9];
+
+		for (var i = 0; i < length; i++)
+		{
+			accessKeyInterleaved[3 * i] = ',';
+			accessKeyInterleaved[(3 * i) + 1] = ' ';
+			accessKeyInterleaved[(3 * i) + 2] = toInterleave[i];
+		}
+
+		interleavedString = new string(accessKeyInterleaved, 0, length * 3);
+	}
+
+	static void GetAccessKeyFromOwner(DependencyObject spOwner, out string accessKey, out DependencyObject scopeOwner)
+	{
+		if (spOwner is FrameworkElement ownerAsFrameworkElement)
+		{
+			accessKey = (string)ownerAsFrameworkElement.GetValue(UIElement.AccessKeyProperty);
+			ownerAsFrameworkElement.GetAccessKeyScopeOwner(out scopeOwner);
+		}
+		else if (spOwner is TextElement ownerAsTextElement)
+		{
+			accessKey = (string)ownerAsTextElement.GetValue(TextElement.AccessKeyProperty);
+			ownerAsTextElement.GetAccessKeyScopeOwner(out scopeOwner);
+		}
+		else
+		{
+			throw new ArgumentException("Invalid argument", nameof(spOwner));
+		}
+	}
+
+	public static string GetAccessKeyMessageFromElement(DependencyObject spOwner)
+	{
+		string prefix;
+		string accessKey;
+		string messageWithoutPrefix;
+
+		DependencyObject akScopeOwner;
+
+		GetAccessKeyFromOwner(spOwner, out accessKey, out akScopeOwner);
+
+		// If no AccessKey was set, return an empty String
+		if (string.IsNullOrEmpty(accessKey))
+		{
+			return "";
+		}
+
+		// If the scope owner exists, grab its sequence and add access keys.
+		AutomationPeer automationPeer = null;
+		if (akScopeOwner != null)
+		{
+			if (akScopeOwner is FrameworkElement akScopeOwnerAsFrameworkElement)
+			{
+				automationPeer = akScopeOwnerAsFrameworkElement.GetOrCreateAutomationPeer();
+			}
+			else if (akScopeOwner is TextElement akScopeOwnerAsTextElement)
+			{
+				automationPeer = akScopeOwnerAsTextElement.GetOrCreateAutomationPeer();
+			}
+			else
+			{
+				throw new ArgumentException("Invalid argument", nameof(akScopeOwner));
+			}
+		}
+
+		prefix = automationPeer?.GetAccessKey() ?? "Alt";
+
+		InterleaveStringWithDelimiters(accessKey, accessKey.Length, out messageWithoutPrefix);
+
+		return prefix + messageWithoutPrefix;
+	}
+}
+}