public override object EditValue(ITypeDescriptorContext context, System.IServiceProvider provider, object value) { if (context != null && context.Instance != null && provider != null) { FrequencyEditorForm dlg = new FrequencyEditorForm(context.Instance as ChannelTV); if(dlg.ShowDialog() == DialogResult.OK) return (context.Instance as ChannelDVB).Frequency; } return null; }