10 reasons to use Sandboxed Solutions

• Sandboxed solutions are secure.
• Sandboxed solutions can be monitored.
• Sandboxed solutions do not affect other sandboxed solutions, well atleast not in other site collections is what I mean.
• Sandboxed solutions do not touch the file system for the most part
• Sandboxed solutions skip application pool recycles, so debugging is not such a pain.
• Sandboxed solutions allow the site collection administrator to perform deployment and upgrades
• Sandboxed solutions make CAS policies look like the out of style hairstyles of 1980s
• The Solution validation framework for sandboxed solutions is exntensible, simply inherit from the SPSolutionValidator base class.
• Sandboxed solutions remove the need for line by line code reviews
• Sandboxed solutions allow you to offer different level of SLAs to different site collections using Resource Quotas.

What is supported by sandboxed solutions?

Basically it is a narrowed down subset of the SharePoint OM. This is controlled with VS2010 by selecting your Visual Studio project as a sandboxed solution. It will hide any methods/classes that are not available automatically.

The following capabilities and elements are available in sandboxed solutions:

• List definitions
• List instances
• Onet.xml
• WebTemplate Feature element instead of Webtemp.xml
• Content Types/Fields
• Navigation
• Module/files
• Feature callouts
• Web Parts derived from WebPart
• Event receivers
  • SPItemEventReceiver
  • SPListEventReceiver
  • SPWebEventReceiver
• Custom Actions
• Workflows

What is not supported by sandboxed solutions?

The following capabilities and elements are not available in sandboxed solutions (from MSDN):

• Custom Action groups
• HideCustomAction element
• Content Type Binding
• Web Application-scoped Features
• Farm-scoped Features
• CustomPropertyToolPart Class
• programmatic workflow

• Event receivers
  • SPLimitedWebPartManager
• timer jobs
• visual WebParts
• SharePoint mapped folders (e.g. "_layouts", and "images")

The following .NET namespaces are not supported by sandboxed solutions:

• ADO.NET
• System.IO
• System.Security.Cryptography
• System.Web.UI.ClientScriptManager