public async Task <IActionResult> OnPostDepartmentsAsync() { MemoryStream stream = new MemoryStream(); await Request.Body.CopyToAsync(stream); stream.Position = 0; using StreamReader reader = new StreamReader(stream); var requestBody = reader.ReadToEnd(); if (requestBody.Length > 0) { var facultyId = Guid.Parse(requestBody); IEnumerable <SelectListItem> departmentsAsSelectList = await _dropDownService.GetDepartments(facultyId); return(new JsonResult(departmentsAsSelectList)); } return(null); }