When creating solutions for the SharePoint sandbox, whether it is for SharePoint 2010 or Office365, the solution ID must be given whenever some kind of code-behind is used. This is because SharePoint needs to know which assembly to use. Without the solution ID SharePoint would just look in the GAC for the assembly, which would produce a 'File could not be found' exception.
I will show how to supply the solution ID for a number of SharePoint components, and also describe a work-around in a case where we cannot specify a solution ID.
