Autogenerated header support for C# language

CHANGELOG.md

@@ -12,6 +12,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Added the title of the API in the VSCode tree view. [#2779](https://github.com/microsoft/kiota/issues/2779)
 - Added capability to serialize and deserialize UUIDs in typescript[#40](https://github.com/microsoft/kiota-typescript/issues/40)
 - Use `import type` statement if the generated code is an interface[#2959](https://github.com/microsoft/kiota/issues/2959)
+- Added auto-generation header for class and enums in CSharp [#2886](https://github.com/microsoft/kiota/issues/2886)
 
 ### Changed
 

src/Kiota.Builder/Writers/CSharp/CodeClassDeclarationWriter.cs

@@ -8,13 +8,15 @@
 namespace Kiota.Builder.Writers.CSharp;
 public class CodeClassDeclarationWriter : BaseElementWriter<ClassDeclaration, CSharpConventionService>
 {
+    public static string AutoGenerationHeader => "// <auto-generated/>";
     public CodeClassDeclarationWriter(CSharpConventionService conventionService) : base(conventionService) { }
     public override void WriteCodeElement(ClassDeclaration codeElement, LanguageWriter writer)
     {
         ArgumentNullException.ThrowIfNull(codeElement);
         ArgumentNullException.ThrowIfNull(writer);
         if (codeElement.Parent?.Parent is CodeNamespace)
         {
+            writer.WriteLine(AutoGenerationHeader);
             codeElement.Usings
                     .Where(x => (x.Declaration?.IsExternal ?? true) || !x.Declaration.Name.Equals(codeElement.Name, StringComparison.OrdinalIgnoreCase)) // needed for circular requests patterns like message folder
                     .Select(static x => x.Declaration?.IsExternal ?? false ?

src/Kiota.Builder/Writers/CSharp/CodeEnumWriter.cs

@@ -8,6 +8,7 @@
 namespace Kiota.Builder.Writers.CSharp;
 public class CodeEnumWriter : BaseElementWriter<CodeEnum, CSharpConventionService>
 {
+    public static string AutoGenerationHeader => "// <auto-generated/>";
     public CodeEnumWriter(CSharpConventionService conventionService) : base(conventionService) { }
     public override void WriteCodeElement(CodeEnum codeElement, LanguageWriter writer)
     {
@@ -19,6 +20,7 @@ public override void WriteCodeElement(CodeEnum codeElement, LanguageWriter write
         var codeNamespace = codeElement.Parent as CodeNamespace;
         if (codeNamespace != null)
         {
+            writer.WriteLine(AutoGenerationHeader);
             foreach (var x in codeElement.Usings
                     .Where(static x => x.Declaration?.IsExternal ?? true)
                     .Select(static x => $"using {(x.Declaration?.Name ?? x.Name).NormalizeNameSpaceName(".")};")

tests/Kiota.Builder.Tests/Writers/CSharp/CodeClassDeclarationWriterTests.cs

@@ -10,6 +10,7 @@
 namespace Kiota.Builder.Tests.Writers.CSharp;
 public class CodeClassDeclarationWriterTests : IDisposable
 {
+    private const string AutoGenerationHeader = "// <auto-generated/>";
     private const string DefaultPath = "./";
     private const string DefaultName = "name";
     private readonly StringWriter tw;
@@ -30,18 +31,29 @@ public CodeClassDeclarationWriterTests()
         };
         root.AddClass(parentClass);
     }
+
     public void Dispose()
     {
         tw?.Dispose();
         GC.SuppressFinalize(this);
     }
+
+    [Fact]
+    public void WritesAutoGeneratedHeader()
+    {
+        codeElementWriter.WriteCodeElement(parentClass.StartBlock, writer);
+        var result = tw.ToString();
+        Assert.Contains(AutoGenerationHeader, result);
+    }
+
     [Fact]
     public void WritesSimpleDeclaration()
     {
         codeElementWriter.WriteCodeElement(parentClass.StartBlock, writer);
         var result = tw.ToString();
         Assert.Contains("public class", result);
     }
+
     [Fact]
     public void WritesImplementation()
     {
@@ -54,6 +66,7 @@ public void WritesImplementation()
         var result = tw.ToString();
         Assert.Contains(":", result);
     }
+
     [Fact]
     public void WritesInheritance()
     {
@@ -66,6 +79,7 @@ public void WritesInheritance()
         var result = tw.ToString();
         Assert.Contains(":", result);
     }
+
     [Fact]
     public void WritesImports()
     {

tests/Kiota.Builder.Tests/Writers/CSharp/CodeEnumWriterTests.cs

@@ -11,6 +11,7 @@
 namespace Kiota.Builder.Tests.Writers.CSharp;
 public class CodeEnumWriterTests : IDisposable
 {
+    private const string AutoGenerationHeader = "// <auto-generated/>";
     private const string DefaultPath = "./";
     private const string DefaultName = "name";
     private readonly StringWriter tw;
@@ -37,6 +38,7 @@ public void Dispose()
         tw?.Dispose();
         GC.SuppressFinalize(this);
     }
+
     [Fact]
     public void WritesEnum()
     {
@@ -48,6 +50,15 @@ public void WritesEnum()
         Assert.Contains(Option.Name, result);
     }
 
+    [Fact]
+    public void WritesAutoGeneratedHeader()
+    {
+        currentEnum.AddOption(Option);
+        writer.Write(currentEnum);
+        var result = tw.ToString();
+        Assert.Contains(AutoGenerationHeader, result);
+    }
+
     [Fact]
     public void NamesDiffer_WritesEnumMember()
     {