You can create a project class library project which holds such classes. Provide the reference of this project in all layers. Sorry, the arrow shows the flow of the data objects not the reference. Reference would be as follows Data Access Layer - Ref of common Business Layer - Ref of Data Access Layer and Ref of Common UI - Ref of Business Layer & ref of Common Download sample project from here. -Rahul Shukla

Create a Common library for Data Transfer objects and share it among all layers. So this would be              (Data Transfer Objects)                    (Data Transfer Objects) Data Layer -----------------------> Business Layer ------------------------> UI Layer

Hi Tina, I would suggest you to go with a event subscription based model to achieve this. Please see Observer Pattern for details. Make one project for Subject & Define all the other dll projects as observers. Let me know if you want to see a working code of it. Regards, Rahul Shukla

Hi, IIS 6.0 or earlier does not support non http protocols. IIS 7 has come up with a feature named WAS (Windows Activation Services). Please see the below article for details - Host a WCF Service in WAS

Do you mean on IIS ?

Hi, Use WCF if these 2 projects are running in different app domains. Ensure to, -Use Named Pipe binding (I assume that both are winform applications and running on same machine) -Implement duplex contract for notifications. Let me know if you need help for implementing this.

Hi Mike, It did work for me on VS 2008. Here is my program - using System; using System.ServiceProcess; namespace ConsoleApplication1 { class Program { static void Main(string[] args) { try { ServiceController service = new ServiceController("<<Your Service Name>>"); service.Stop(); TimeSpan timeout = TimeSpan.FromMilliseconds(10000); service.WaitForStatus(ServiceControllerStatus.Stopped, timeout); if (service.Status == ServiceControllerStatus.Stopped) { service.Start(); } } catch { // ... } } } } Are you getting any specific error ?