c# sample code for ALB listner Rule Condition

[Waqiah]

Looking for c# sample code to add a new rule to an ALB listener that would check if the Host header contains a certain string before forwarding the request to a specific target group.

The following has been tried:
................
var alb = ApplicationLoadBalancer.FromLookup(scope, $"Get{props.ApplicationLoadBalancer}", new ApplicationLoadBalancerLookupOptions()
{
LoadBalancerArn = props.ApplicationLoadBalancer?.GetDescription()
});

if (alb == null)
{
throw new ArgumentException("Invalid Application Load Balancer provided.");
}

alb.Listeners.First().AddTargetGroups($"{props.SiteUrl}LoadBalancerRule", new AddApplicationTargetGroupsProps()
{
Conditions = new ListenerCondition[] { ListenerCondition.HostHeaders(new string[] { $"{props.SiteUrl}.*" }) },
TargetGroups = new[] { targetGroup }
});
................

However the following error was received:
Unhandled exception. System.Exception: Error: .listeners can only be accessed if the class was constructed as an owned, not looked up, load balancer

I understand that this error could be due to the "from_lookup" method in the "elbv2.ApplicationLoadBalancer" class not currently being supported.

Looking for any suggestions/workarounds.