C#: How to programmatically check a web service is up and running?

I need to create an C# application that will monitor whether a set of web services are up and running. User will select a service name from a dropdown. The program need to test with the corresponding service URL and show whether the service is running. What is the best way to do it? One way I am thinking of is to test whether we are able to download the wsdl. IS there a better way?