How to: Set Startup Projects
You can specify which project or projects within a multi-project solution Visual Studio will build and debug first.
To set a single startup project
In Solution Explorer, select the desired startup project within your solution.
On the Project menu, choose Set as StartUp Project.
To set multiple startup projects
In Solution Explorer, select your solution.
On the View menu, choose Property Pages.
The Solution Property Pages dialog box opens.
Select Common Properties, and choose Startup Project.
The Startup Project properties for your solution are displayed.
Select the Multiple Startup Project option.
Click the Action for each startup project, and from the drop-down list of options, choose Start or Start without debugging (if you do not wish to run the debugger on startup).
To change the order in which projects will be opened, debugged, and run, select projects, and click Move Up or Move Down.
Click OK to save these settings.