Merge pull request #3544 from microsoft/bugfix/csharp-override

- fixes serialization/deserialization for inheritance in dotnet

CHANGELOG.md

@@ -20,6 +20,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Changed
 
 - Fixed missing imports for method parameters that are query parameters.
+- Replaces the use of "new" by "override" and "virtual" in CSharp models.
 - Fixed query parameters type mapping for arrays. [#3354](https://github.com/microsoft/kiota/issues/3354)
 - Fixed bug where base64url and decimal types would not be generated properly in Java.
 - Fixed bug where symbol name cleanup would not work on forward single quotes characters [#3426](https://github.com/microsoft/kiota/issues/3426).

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

@@ -599,7 +599,13 @@ private static string GetBaseSuffix(bool isConstructor, bool inherits, CodeClass
     private void WriteMethodPrototype(CodeMethod code, CodeClass parentClass, LanguageWriter writer, string returnType, bool inherits, bool isVoid)
     {
         var staticModifier = code.IsStatic ? "static " : string.Empty;
-        var hideModifier = inherits && code.IsOfKind(CodeMethodKind.Serializer, CodeMethodKind.Deserializer, CodeMethodKind.Factory) ? "new " : string.Empty;
+        var hideModifier = (inherits, code.Kind) switch
+        {
+            (true, CodeMethodKind.Serializer or CodeMethodKind.Deserializer) => "override ",
+            (false, CodeMethodKind.Serializer or CodeMethodKind.Deserializer) => "virtual ",
+            (true, CodeMethodKind.Factory) => "new ",
+            _ => string.Empty
+        };
         var genericTypePrefix = isVoid ? string.Empty : "<";
         var genericTypeSuffix = code.IsAsync && !isVoid ? ">" : string.Empty;
         var isConstructor = code.IsOfKind(CodeMethodKind.Constructor, CodeMethodKind.ClientConstructor, CodeMethodKind.RawUrlConstructor);