Use C# DLL as Web Service

Using .Net 4 we can host a DLL as WebServiceand here is how to do it. All you have to do is the following: Create an Interface for the DLL Code Add Reference to "using System.ServiceModel" in the code

using System.ServiceModel;

namespace Dll_as_WS
{
    [ServiceContract()]
    interface IWS_Class1
    {
        [OperationContract()]
        int AddNum(int one, int two);

    }
}

then you shold implement the interface like

using System.ServiceModel;
using System.ServiceModel.Description;

namespace Dll_as_WS
{
    // Service Implementation
    public class WS_Class1:IWS_Class1
    {
        public int AddNum(int one, int two)
        {
            return one + two;
        }
    }
}

The reason why i am using "System.ServiceModel.Description" reference is because we Need a host application to host this DLL as WS. So Add a new Class call it "Host_WS_Class1"

// Hosting WS
    public class Host_WS_Class1
    {
        public Uri httpUrl { get; set; }
        public string Status { get; set; }
        private ServiceHost WsSvcHost;
        public bool IsLive { get; set; }
    
        public Host_WS_Class1(string HostingURL)
        {
            //Create a URI to serve as the base address
            httpUrl = new Uri(HostingURL);
            //Create ServiceHost
            WsSvcHost = new ServiceHost(typeof(Dll_as_WS.WS_Class1), httpUrl);
            //Add a service endpoint
            WsSvcHost.AddServiceEndpoint(typeof(Dll_as_WS.IWS_Class1), new WSHttpBinding(), "");
            //Enable metadata exchange
            ServiceMetadataBehavior svcMetaBehaviour = new ServiceMetadataBehavior();
            svcMetaBehaviour.HttpGetEnabled = true;
            WsSvcHost.Description.Behaviors.Add(svcMetaBehaviour);
            IsLive = false;


        }

        public string Start()
        {
            //Start the Service
            WsSvcHost.Open();
            IsLive = true;
            Status = string.Format("Service started at {0}", DateTime.Now.ToString().Replace('/', ':'));
            return Status;
        }

        public string Stop()
        {
            //Start the Service
            WsSvcHost.Close();
            IsLive = false;
            Status = string.Format("Service stopped at {0}", DateTime.Now.ToString().Replace('/', ':'));
            return Status;
        }
    }

Now all you need is an application to call/host this DLL.

 Dll_as_WS.Host_WS_Class1 hostCls = new Host_WS_Class1("http://localhost:5000/NewSvc");
            Console.WriteLine(hostCls.Start());
            Console.ReadKey();