public static void ValidateProperty(this KeyValuePair <XName, InstanceValue> property, bool allowDelete) { if (property.Key == null) { throw Fx.Exception.AsError(new InvalidOperationException(SRCore.MetadataCannotContainNullKey)); } if (property.Value == null) { throw Fx.Exception.AsError(new InvalidOperationException(SRCore.MetadataCannotContainNullValue(property.Key))); } if (!allowDelete && property.Value.IsDeletedValue) { throw Fx.Exception.AsError(new InvalidOperationException(SRCore.InitialMetadataCannotBeDeleted(property.Key))); } }