How know if ModelState contains errors

Question

When a form is posted in my controller, I make the following check:

if(ModelState.IsValid)

If the model is not valid, errors are added to the <

Answer 1

a little addition to @Dimitrov answer:

It's important to use single qoutes around the helper. Otherwise, that ending semicolon ; cause problems. Nether you can write it, nor you can't, at all cases it cause a syntax error. Unless you put those single quotes around the helper as I mentioned.