How to get Custom validation error?

Question

Suppose I have entity Person with properties typeid and salary. I build a business rule for this two properties like:

public static partial class MyRules
    {
        public static ValidationResult Rule1(Person p, ValidationContext context)
        {           

            if ((p.typeid == 1) && ((p.salary == null))
            {
                return new ValidationResult("type 1 must should have salary",
                                            new string[] { "Salary" });
            }

            return ValidationResult.Success;
        }
    }

The code is put at server side with share.cs.

So when the rule is violated, I wil have SubmitOperation.HasError = true; This kind of error only after call SubmitChanges. and the error does not display in ValidationSummary

So when SubmitOperation.HasError = true; how can I know SubmitOperation error is validation error not other error? When I can identify this error as validation error, how can I get the validation error message "type 1 must should have salary" and show it to user?