Represents a multicolumn field type.
Assembly: Microsoft.SharePoint (in Microsoft.SharePoint.dll)
Available in Sandboxed Solutions: Yes
Available in SharePoint Online
An SPFieldMulitColumn object emulates a field that contains multiple values. In actuality, the class contains a single string value, in which the values of the various "columns" are separated by special delimiter characters.
Data for fields is stored in the content database as a non-sortable SQL data type. For that reason, columns based on the field type or on custom field types derived from it are not sortable.Notes to Inheritors
In SharePoint Foundation, columns based on custom field types are read-only in Datasheet view.