However, The swagger UI is coming up if i comment below line in StructuremapWebApi.cs
GlobalConfiguration.Configuration.DependencyResolver = new StructureMapWebApiDependencyResolver(container);
But, The DI will not work if i comment above line. Is there any solution for this.
Unfortunately, I'm not sure we can help with that.
Swagger UI, as a set of static html/css/js files just 'works'. Any other product you use it within should just host it as the static files they are, while injecting the configuration in one of the available methods. We don't have any specific knowledge about structuremap to offer help with it directly.