XebiaLabs.Deployit.UI.Validation.ValidatableViewModel.Validate C# (CSharp) Method

        private List<string> Validate(ValidatableViewModel vm)
        {
            if (vm == null)
            {
                throw new ArgumentNullException("vm");
            }

            var result = ValidateCore();
            result.AddRange(from item in _validationAttributeDictionary
                let value = item.Key.GetValue(vm, null)
                from validationItem in item.Value
                select validationItem.Validate(this, value)
                into error
                where !string.IsNullOrEmpty(error)
                select error);
            return result;
        }