create MobileServiceClient instance

gistfile1.cs

using Microsoft.WindowsAzure.MobileServices;

namespace SensorDemoMobileServices
{
    public partial class Program
    {
        //TODO: add your mobile service URI and app key below from the Windows Azure Portal https://manage.windowsazure.com 
       public static MobileServiceClient MobileService = new MobileServiceClient(
           new Uri("http://<your Windows Azure Mobile Service subdomain >.azure-mobile.net/"),
           "<your Windows Azure Mobile Service App Key> "
       );  

      ....
    }
}