Appendix

Errors

Error message	Possible reason
ODataException: Invalid JSON. An unexpected comma was found in scope 'Object'. A comma is only valid between properties of an object or between elements of an array.	A comma appended to the last property of a JSON formatted request body.

General developer notes

OData

• IActionResult is used when multiple return types are possible, otherwise ActionResult<T> can be used. The type property of ProducesResponseTypeAttribute can be excluded for ActionResult<T>.

• OData functions can only be HttpGet, OData actions can only be HttpPost.

• By protocol specification enums are serialized using the enum member's string, not its value.

• Routing conventions (only partly applicable for AspNetCore.OData v.8).

• $ref is not supported.

• Reasonably accurate OData examples.

Swashbuckle

• Explicit From parameter bindings are required, otherwise Swashbuckle will describe them as query parameters by default. Code comments of parameters decorated with FromForm do not show up (#2519).