diff --git a/modules/openapi-generator/src/main/resources/csharp-netcore/ApiClient.mustache b/modules/openapi-generator/src/main/resources/csharp-netcore/ApiClient.mustache
index 3e21a800e08e..e874041b3e7c 100644
--- a/modules/openapi-generator/src/main/resources/csharp-netcore/ApiClient.mustache
+++ b/modules/openapi-generator/src/main/resources/csharp-netcore/ApiClient.mustache
@@ -327,9 +327,9 @@ namespace {{packageName}}.Client
                     var bytes = ClientUtils.ReadAsBytes(fileParam.Value);
                     var fileStream = fileParam.Value as FileStream;
                     if (fileStream != null)
-                        FileParameter.Create(fileParam.Key, bytes, System.IO.Path.GetFileName(fileStream.Name));
+                        request.Files.Add(FileParameter.Create(fileParam.Key, bytes, System.IO.Path.GetFileName(fileStream.Name)));
                     else
-                        FileParameter.Create(fileParam.Key, bytes, "no_file_name_provided");
+                        request.Files.Add(FileParameter.Create(fileParam.Key, bytes, "no_file_name_provided"));
                 }
             }
 
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools.Test/Api/PetApiTests.cs b/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools.Test/Api/PetApiTests.cs
index 4d946eca6a89..19b7a6c81baa 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools.Test/Api/PetApiTests.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools.Test/Api/PetApiTests.cs
@@ -279,11 +279,11 @@ public void UploadFileTest()
             Stream _imageStream = _assembly.GetManifestResourceStream("Org.OpenAPITools.Test.linux-logo.png");
             PetApi petApi = new PetApi();
             // test file upload with form parameters
-            //petApi.UploadFile(petId, "new form name", _imageStream);
+            petApi.UploadFile(petId, "new form name", _imageStream);
 
             // test file upload without any form parameters
             // using optional parameter syntax introduced at .net 4.0
-            //petApi.UploadFile(petId: petId, file: _imageStream);
+            petApi.UploadFile(petId: petId, file: _imageStream);
         }
         
         /// <summary>
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Client/ApiClient.cs b/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Client/ApiClient.cs
index f500f1e5b9e2..0071562ed269 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Client/ApiClient.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Client/ApiClient.cs
@@ -330,9 +330,9 @@ private RestRequest newRequest(
                     var bytes = ClientUtils.ReadAsBytes(fileParam.Value);
                     var fileStream = fileParam.Value as FileStream;
                     if (fileStream != null)
-                        FileParameter.Create(fileParam.Key, bytes, System.IO.Path.GetFileName(fileStream.Name));
+                        request.Files.Add(FileParameter.Create(fileParam.Key, bytes, System.IO.Path.GetFileName(fileStream.Name)));
                     else
-                        FileParameter.Create(fileParam.Key, bytes, "no_file_name_provided");
+                        request.Files.Add(FileParameter.Create(fileParam.Key, bytes, "no_file_name_provided"));
                 }
             }
 
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Client/ApiClient.cs b/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Client/ApiClient.cs
index 12d3d49f7386..f68650fa7bc9 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Client/ApiClient.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Client/ApiClient.cs
@@ -331,9 +331,9 @@ private RestRequest newRequest(
                     var bytes = ClientUtils.ReadAsBytes(fileParam.Value);
                     var fileStream = fileParam.Value as FileStream;
                     if (fileStream != null)
-                        FileParameter.Create(fileParam.Key, bytes, System.IO.Path.GetFileName(fileStream.Name));
+                        request.Files.Add(FileParameter.Create(fileParam.Key, bytes, System.IO.Path.GetFileName(fileStream.Name)));
                     else
-                        FileParameter.Create(fileParam.Key, bytes, "no_file_name_provided");
+                        request.Files.Add(FileParameter.Create(fileParam.Key, bytes, "no_file_name_provided"));
                 }
             }