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?

Note: The purpose of this application is that the user need to know only the service name. He need not remember/store the corresponding URL of the service.

I need a website version and a desktop application version of this C# application.

Note: Existing services are using WCF. But in future a non-WCF service may get added.

Note: My program will not be aware of (or not interested in ) operations in the service. So I cannot call a service operation.

REFERENCE

1. How to check if a web service is up and running without using ping?
2. C program-How do I check if a web service is running