[Csharp-client] Complex form parameters are not serialized as application/json (OpenAPITools#5849)

* [csharp-client] Complex form parameters are now correctly serialized as json.

* Updated csharp samples

Co-authored-by: Olivier Leonard <[email protected]>

Author: 2 people

modules/openapi-generator/src/main/resources/csharp/api.mustache

@@ -384,7 +384,7 @@ namespace {{packageName}}.{{apiPackage}}
             if ({{paramName}} != null) localVarHeaderParams.Add("{{baseName}}", this.Configuration.ApiClient.ParameterToString({{paramName}})); // header parameter
             {{/headerParams}}
             {{#formParams}}
-            if ({{paramName}} != null) {{#isFile}}localVarFileParams.Add("{{baseName}}", this.Configuration.ApiClient.ParameterToFile("{{baseName}}", {{paramName}}));{{/isFile}}{{^isFile}}localVarFormParams.Add("{{baseName}}", this.Configuration.ApiClient.ParameterToString({{paramName}})); // form parameter{{/isFile}}
+            if ({{paramName}} != null) {{#isFile}}localVarFileParams.Add("{{baseName}}", this.Configuration.ApiClient.ParameterToFile("{{baseName}}", {{paramName}}));{{/isFile}}{{^isFile}}localVarFormParams.Add("{{baseName}}", this.Configuration.ApiClient.{{#isPrimitiveType}}ParameterToString{{/isPrimitiveType}}{{^isPrimitiveType}}Serialize{{/isPrimitiveType}}({{paramName}})); // form parameter{{/isFile}}
             {{/formParams}}
             {{#bodyParam}}
             if ({{paramName}} != null && {{paramName}}.GetType() != typeof(byte[]))

samples/client/petstore/csharp/OpenAPIClient/src/Org.OpenAPITools/Api/FakeApi.cs

@@ -2403,7 +2403,7 @@ public async System.Threading.Tasks.Task<ApiResponse<ModelClient>> TestClientMod
             if (enumQueryDouble != null) localVarQueryParams.AddRange(this.Configuration.ApiClient.ParameterToKeyValuePairs("", "enum_query_double", enumQueryDouble)); // query parameter
             if (enumHeaderStringArray != null) localVarHeaderParams.Add("enum_header_string_array", this.Configuration.ApiClient.ParameterToString(enumHeaderStringArray)); // header parameter
             if (enumHeaderString != null) localVarHeaderParams.Add("enum_header_string", this.Configuration.ApiClient.ParameterToString(enumHeaderString)); // header parameter
-            if (enumFormStringArray != null) localVarFormParams.Add("enum_form_string_array", this.Configuration.ApiClient.ParameterToString(enumFormStringArray)); // form parameter
+            if (enumFormStringArray != null) localVarFormParams.Add("enum_form_string_array", this.Configuration.ApiClient.Serialize(enumFormStringArray)); // form parameter
             if (enumFormString != null) localVarFormParams.Add("enum_form_string", this.Configuration.ApiClient.ParameterToString(enumFormString)); // form parameter
 
 

samples/client/petstore/csharp/OpenAPIClientNetStandard/src/Org.OpenAPITools/Api/FakeApi.cs

@@ -2403,7 +2403,7 @@ public async System.Threading.Tasks.Task<ApiResponse<ModelClient>> TestClientMod
             if (enumQueryDouble != null) localVarQueryParams.AddRange(this.Configuration.ApiClient.ParameterToKeyValuePairs("", "enum_query_double", enumQueryDouble)); // query parameter
             if (enumHeaderStringArray != null) localVarHeaderParams.Add("enum_header_string_array", this.Configuration.ApiClient.ParameterToString(enumHeaderStringArray)); // header parameter
             if (enumHeaderString != null) localVarHeaderParams.Add("enum_header_string", this.Configuration.ApiClient.ParameterToString(enumHeaderString)); // header parameter
-            if (enumFormStringArray != null) localVarFormParams.Add("enum_form_string_array", this.Configuration.ApiClient.ParameterToString(enumFormStringArray)); // form parameter
+            if (enumFormStringArray != null) localVarFormParams.Add("enum_form_string_array", this.Configuration.ApiClient.Serialize(enumFormStringArray)); // form parameter
             if (enumFormString != null) localVarFormParams.Add("enum_form_string", this.Configuration.ApiClient.ParameterToString(enumFormString)); // form parameter
 
 

samples/client/petstore/csharp/OpenAPIClientWithPropertyChanged/src/Org.OpenAPITools/Api/FakeApi.cs

@@ -2403,7 +2403,7 @@ public async System.Threading.Tasks.Task<ApiResponse<ModelClient>> TestClientMod
             if (enumQueryDouble != null) localVarQueryParams.AddRange(this.Configuration.ApiClient.ParameterToKeyValuePairs("", "enum_query_double", enumQueryDouble)); // query parameter
             if (enumHeaderStringArray != null) localVarHeaderParams.Add("enum_header_string_array", this.Configuration.ApiClient.ParameterToString(enumHeaderStringArray)); // header parameter
             if (enumHeaderString != null) localVarHeaderParams.Add("enum_header_string", this.Configuration.ApiClient.ParameterToString(enumHeaderString)); // header parameter
-            if (enumFormStringArray != null) localVarFormParams.Add("enum_form_string_array", this.Configuration.ApiClient.ParameterToString(enumFormStringArray)); // form parameter
+            if (enumFormStringArray != null) localVarFormParams.Add("enum_form_string_array", this.Configuration.ApiClient.Serialize(enumFormStringArray)); // form parameter
             if (enumFormString != null) localVarFormParams.Add("enum_form_string", this.Configuration.ApiClient.ParameterToString(enumFormString)); // form parameter