public void OnValidate(Radical.Validation.ValidationContext <RequireValidationSampleViewModel> context)
        {
            if (context.PropertyName == null)
            {
                var displayname = GetPropertyDisplayName(nameof(Sample));

                context.Results.AddError(() => Sample, displayname, new[] { "This is fully custom, and works even on non-bound properties such as 'Sample'." });
            }
        }
        public void OnValidate(Radical.Validation.ValidationContext <RequireValidationSampleViewModel> context)
        {
            var displayname = this.ValidationService.GetPropertyDisplayName(this, o => o.Sample);

            context.Results.AddError(() => this.Sample, displayname, new[] { "This is fully custom, and works even on non-bound properties such as 'Sample'." });
        }