[XC] trim x:Name values

fixes #27121

Author: StephaneDelcroix

src/Controls/src/Build.Tasks/SetFieldVisitor.cs

@@ -30,7 +30,7 @@ public void Visit(ValueNode node, INode parentNode)
 		{
 			if (!IsXNameProperty(node, parentNode))
 				return;
-			var field = Context.Body.Method.DeclaringType.Fields.SingleOrDefault(fd => fd.Name == (string)node.Value);
+			var field = Context.Body.Method.DeclaringType.Fields.SingleOrDefault(fd => fd.Name == ((string)node.Value).Trim());
 			if (field == null)
 				return;
 			Context.IL.Emit(OpCodes.Ldarg_0);

src/Controls/tests/Xaml.UnitTests/Issues/Maui27121.xaml

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="utf-8"?>
+<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
+             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
+             xmlns:local="clr-namespace:Microsoft.Maui.Controls.Xaml.UnitTests"
+             x:Class="Microsoft.Maui.Controls.Xaml.UnitTests.Maui27121">
+    <Label x:Name=" label0" Text =" Values: 1234" TextColor="Black"/> 
+</ContentPage>

src/Controls/tests/Xaml.UnitTests/Issues/Maui27121.xaml.cs

@@ -0,0 +1,44 @@
+using System;
+using System.ComponentModel;
+using System.Diagnostics.CodeAnalysis;
+using System.Globalization;
+using System.Linq;
+using Microsoft.Maui.ApplicationModel;
+using Microsoft.Maui.Controls.Core.UnitTests;
+using Microsoft.Maui.Dispatching;
+using Microsoft.Maui.UnitTests;
+using Mono.Cecil;
+using Mono.Cecil.Cil;
+using NUnit.Framework;
+
+namespace Microsoft.Maui.Controls.Xaml.UnitTests;
+
+public partial class Maui27121
+{
+	public Maui27121() => InitializeComponent();
+
+	public Maui27121(bool useCompiledXaml)
+	{
+		//this stub will be replaced at compile time
+	}
+
+	[TestFixture]
+	class Test
+	{
+		[SetUp]
+		public void Setup()
+		{
+			Application.SetCurrentApplication(new MockApplication());
+			DispatcherProvider.SetCurrent(new DispatcherProviderStub());
+		}
+
+		[TearDown] public void TearDown() => AppInfo.SetCurrent(null);
+
+		[Test]
+		public void XNameAreTrimmed([Values] bool useCompiledXaml)
+		{
+			var page = new Maui27121(useCompiledXaml);
+            Assert.That(page.label0, Is.Not.Null);
+		}
+	}
+}