Fix issue with template processing (#26196)

* Fix issue with template processing

The template is processing the actual code

* Added a test

* Fix the tests

* Add temporary test for CollectionViewHandler2

* Move temporary test comment to correct location

* Remove redundant `#endif` assertions in tests

src/Templates/src/templates/maui-mobile/MauiProgram.cs

@@ -20,9 +20,11 @@ public static MauiApp CreateMauiApp()
 			.ConfigureSyncfusionToolkit()
 			.ConfigureMauiHandlers(handlers =>
 			{
+//-:cnd:noEmit
 #if IOS || MACCATALYST
 				handlers.AddHandler<Microsoft.Maui.Controls.CollectionView, Microsoft.Maui.Controls.Handlers.Items2.CollectionViewHandler2>();
 #endif
+//+:cnd:noEmit
 			})
 #endif
 			.ConfigureFonts(fonts =>

src/TestUtils/src/Microsoft.Maui.IntegrationTests/BaseTemplateTests.cs

@@ -19,4 +19,18 @@ protected void EnableTizen(string projectFile)
 			{ "</TargetFrameworks> -->", "</TargetFrameworks>" },
 		});
 	}
+
+	protected void AssertContains(string expected, string actual)
+	{
+		Assert.IsTrue(
+			actual.Contains(expected, StringComparison.Ordinal),
+			$"Expected string '{actual}' to contain '{expected}'.");
+	}
+
+	protected void AssertDoesNotContain(string expected, string actual)
+	{
+		Assert.IsFalse(
+			actual.Contains(expected, StringComparison.Ordinal),
+			$"Expected string '{actual}' to not contain '{expected}'.");
+	}
 }

src/TestUtils/src/Microsoft.Maui.IntegrationTests/SimpleTemplateTest.cs

@@ -1,4 +1,4 @@
-using System.Xml.Linq;
+using System.Xml.Linq;
 
 namespace Microsoft.Maui.IntegrationTests;
 
@@ -329,4 +329,32 @@ public void BuildWithDifferentVersionNumber(string id, string config, string dis
 		Assert.IsTrue(DotnetInternal.Build(projectFile, config, properties: buildProps, msbuildWarningsAsErrors: true),
 			$"Project {Path.GetFileName(projectFile)} failed to build. Check test output/attachments for errors.");
 	}
+
+	// This test is super temporary and is just for the interim
+	// while we productize the CollectionViewHandler2. Once we
+	// ship it as the default, this test will fail and can be deleted.
+	[Test]
+	[TestCase("maui", DotNetCurrent, "", false)]
+	[TestCase("maui", DotNetCurrent, "--sample-content", true)]
+	public void SampleShouldHaveHandler2Registered(string id, string framework, string additionalDotNetNewParams, bool shouldHaveHandler2)
+	{
+		var projectDir = TestDirectory;
+		var programFile = Path.Combine(projectDir, "MauiProgram.cs");
+
+		Assert.IsTrue(DotnetInternal.New(id, projectDir, framework, additionalDotNetNewParams),
+			$"Unable to create template {id}. Check test output for errors.");
+
+		var programContents = File.ReadAllText(programFile);
+
+		if (shouldHaveHandler2)
+		{
+			AssertContains("#if IOS || MACCATALYST", programContents);
+			AssertContains("handlers.AddHandler<Microsoft.Maui.Controls.CollectionView, Microsoft.Maui.Controls.Handlers.Items2.CollectionViewHandler2>();", programContents);
+		}
+		else
+		{
+			AssertDoesNotContain("#if IOS || MACCATALYST", programContents);
+			AssertDoesNotContain("handlers.AddHandler<Microsoft.Maui.Controls.CollectionView, Microsoft.Maui.Controls.Handlers.Items2.CollectionViewHandler2>();", programContents);
+		}
+	}
 }