ASP.NET complex validation in business / service layer - asp.net

Question

I am asking this because after long time searching I haven't found a good answer on this yet...
Here is what I want:
Example: I have a domain model "JobPosting" which a user should be able to change state to published, if it is still a draft. Before publishing I must not only validate the model properties I must also validate many different requirements regarding the user account, it's registered company etc. All this validation logic is put into a service layer. So far so good...
This is how my service layer looks like:
public IValidationResult ValidatePublish(JobPosting jobPosting){
...
}
public void Publish(JobPosting jobPosting){
jobPosting.State = JobPostingState.Published;
...
}
Any my controller:
public ActionResult Publish(PublishViewModel model){
...
var validationResult = _jobService.ValidatePublish(jobPosting);
if(validationResult.Success){
_jobService.Publish(jobPosting);
...
}
...
}
And here now my questions:
I want to be able to call the ValidatePublish from the controller to show validation errors in the view. However I must never be able to publish a job when validation fails.
So to have my code more robust I added a second validation check in my Publish method in service layer:
public void Publish(JobPosting jobPosting){
if(ValidatePublish(jobPosting).Success){
jobPosting.State = JobPostingState.Published;
...
}
}
but I have not such a good feeling with this approach because now I am calling the validation twice when validation is OK during each controller publish request.
What do you think. Is the second call to much? Is there a better approach?
I am asking because my whole application looks like that and if I would ever forget a validation call in controller I might end up with an not allowed domain model state in database. That's why I added the second validation check in each service method.
Thanks in advance for your thoughts on this!!!

Answer 1

One quick solution might be to have the Publisher class require the JobPosting and IValidationResult objects as arguments.
public void Publish(JobPosting jobPosting, IValidationResult validation)
{
if (validation.IsValid)
{
jobPosting.State = JobPostingState.Published;
// other work here...
}
}
Your Controller can then call the Validator, receive an IValidationResult and pass that back to the presentation layer if needed. Otherwise pass on to Publisher
public ActionResult Publish(PublishViewModel model)
{
var validationResult = _jobService.ValidatePublish(jobPosting);
if(validationResult.Success) _jobService.Publish(jobPosting, validationResult);
else return View("error", validationResult);
}
Edit:
A cleaner solution may be to have the Publisher class return a PublishAttempt result.
public class PublishAttempt : IValidationResult
{
public enum AttemptOutcome {get; set;}
}
public ActionResult Publish(PublishViewModel model)
{
var attempt = _jobService.Publish(jobPosting);
if (attempt.Success) return View("success");
else return View("error", attempt.ValidationResults);
}

Answer 2

The following just came into my mind... what do you think:
I change my service method to:
public IValidationResult Publish(JobPosting jobPosting, bool validateOnly = false){
var validationResult = ValidatePublish(jobPosting);
if(validateOnly) return validationResult;
jobPosting.State = JobPostingState.Published;
...
return validationResult;
}
And then in controller I always call only the Publish method and not the extra ValidatePublish anymore:
public ActionResult Publish(PublishViewModel model)
{
var validationResult = _jobService.Publish(jobPosting);
if(!validationResult.Success) return View("error", validationResult);
}
And when I need only simple validation I do
var validationResult = _jobService.Publish(jobPosting, true);
Is this okey to do it like that?
Or is it not good looking if a normal service call returns IValidationResult?