AWS SDK for .NET Documentation
VpcId Property
AmazonAmazon.RDS.ModelOptionGroupVpcId Did this page help you?   Yes   No    Tell us about it...
If AllowsVpcAndNonVpcInstanceMemberships is 'false', this field is blank. If AllowsVpcAndNonVpcInstanceMemberships is 'true' and this field is blank, then this option group can be applied to both VPC and non-VPC instances. If this field contains a value, then this option group can only be applied to instances that are in the VPC indicated by this field.
Declaration Syntax
C#
public string VpcId { get; set; }

Assembly: AWSSDK (Module: AWSSDK) Version: 1.5.60.0 (1.5.60.0)