Is creating SharePoint sandbox field types possible?

Question

I want to create custom field type for SharePoint Online. Therefore, AFAIK, it must be sandbox solution. Is there any possibility to create this? Or something that allows me to work on "single item level" on the list (not in edit form but on the list). Maybe some option in item menu or sth?

Answer 1

you have to remember that SharePoint Sandbox Model doesn't offer custom FieldTypes.

There is a really good introduction for Sandboxed SharePoint Solutions on MSDN (http://goo.gl/uXGLo).

SPIs like

• ContentTypes
• SiteColumns
• Lists

could easily be created by using CAML (SharePoint XML-DSL) or by custom .NET Code

Answer 2

Only fields that use a built-in SharePoint Foundation field type, or a custom field type that is previously installed in a farm solution, are possible. A custom field type cannot be deployed in a sandboxed solution.

Answer 3

Yes.

For XML support, see Sandboxed Solution Considerations:

Sandboxed solutions support the following capabilities and elements:

...

Content Types/Fields

For API support, see SPFieldCollection.Add:

Available in SharePoint Online

P.S. It is possible to deploy farm solutions to SharePoint Online in some circumstances. But it is so painful that it should be avoided unless absolutely necessary.