In the previous recipe, we learnt how to create a site column using the SharePoint object model. In this recipe, we will create a site column using a declarative XML and add it to the contacts content type.
Contacts content type provides a way to store the contacts in SharePoint. It provides various columns to store contact's name, phone number, fax, web page, and so on. Out of the box, it does not provide a way to categorize these contacts. We will extend this content type so we can categorize our contacts as sales lead, customer, or vendor
Launch your Visual Studio 2010 IDE as an administrator (right-click the shortcut and select Run as administrator).
Select File | New | Project. The new project wizard dialog box will be displayed (make sure to select .NET Framework 3.5 in the top drop-down box).
Select Content Type project under Visual C# | SharePoint | 2010 node from...