Merge pull request #4895 from vvdb-architecture/feature/csharppartialclass

Implemented partial class model declarations.

Author: baywet

CHANGELOG.md

@@ -7,6 +7,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Changed
+- Implemented partial class model declarations. [4894](https://github.com/microsoft/kiota/issues/4894)
+
 ### Added
 
 ### Changed

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

@@ -38,7 +38,7 @@ public override void WriteCodeElement(ClassDeclaration codeElement, LanguageWrit
         bool hasDescription = conventions.WriteLongDescription(parentClass, writer);
         conventions.WriteDeprecationAttribute(parentClass, writer);
         if (!hasDescription) writer.WriteLine("#pragma warning disable CS1591");
-        writer.WriteLine($"public class {codeElement.Name.ToFirstCharacterUpperCase()} {derivation}");
+        writer.WriteLine($"public partial class {codeElement.Name.ToFirstCharacterUpperCase()} {derivation}");
         if (!hasDescription) writer.WriteLine("#pragma warning restore CS1591");
         writer.StartBlock();
     }

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

@@ -51,7 +51,7 @@ public void WritesSimpleDeclaration()
     {
         codeElementWriter.WriteCodeElement(parentClass.StartBlock, writer);
         var result = tw.ToString();
-        Assert.Contains("public class", result);
+        Assert.Contains("public partial class", result);
     }
 
     [Fact]