If we try to add a new silver light project to a solution, then Visual studio prompts with the following dialogue box.
So that we can enable debugging on this newly created silver light application. However if we wanted to add an existing silver light application to a solution which contains a website project then we have to explicitly enable debugging on this silver light application, otherwise Visual studio wont debug this silver light application, when we set the Web application as the start up project.
To enable debugging on this newly added existing silver light project.
1) In solution Explorer, Right click on the Web Project and select ‘Property Pages’ .Here is the screen shot to select ‘Property Pages’
2) In ‘Property pages’ Window in ‘Start Options’ , make sure that the check boxes ‘ASP.NET’ and ‘Silverlight ‘ both are selected.
3) Select ‘Silverlight Application’ then Click on the ‘Add’ button, it will open the following window. Select the check box ‘Enable Silverlight Debugging’ then press ‘Apply’ then ‘Ok’.