How to return a specific status code and no contents from Controller?

this.HttpContext.Response.StatusCode = 418; // I'm a teapot

How to end the request?

Try other solution, just:

return StatusCode(418);

You could use StatusCode(???) to return any HTTP status code.

Also, you can use dedicated results:

Success:

• return Ok() ← Http status code 200
• return Created() ← Http status code 201
• return NoContent(); ← Http status code 204

Client Error:

• return BadRequest(); ← Http status code 400
• return Unauthorized(); ← Http status code 401
• return NotFound(); ← Http status code 404

More details:

• ControllerBase Class (Thanks @Technetium)
• StatusCodes.cs (consts aviable in ASP.NET Core)
• HTTP Status Codes on Wiki
• HTTP Status Codes IANA