[c#] ModelState.IsValid == false, why?

Sometimes a binder throwns an exception with no error message. You can retrieve the exception with the following snippet to find out whats wrong:

(Often if the binder is trying to convert strings to complex types etc)

 if (!ModelState.IsValid)
            {
var errors = ModelState.SelectMany(x => x.Value.Errors.Select(z => z.Exception));

// Breakpoint, Log or examine the list with Exceptions.

  }