How to: Add a Column to a List
Last modified: October 01, 2009
Applies to: SharePoint Foundation 2010
You can specify columns in a list definition, so that each time a user provisions a list of that type, SharePoint Foundation includes the column on the list by default. List definitions can be included in Features. For more information, see Using Features in SharePoint Foundation.
After a user provisions a list, you can add columns to that list through the SharePoint Foundation object model.
If you want to add a column to a list definition that is part of a Feature, you must add the necessary XML element to the list definition. Then, when a user provisions a list of that type, the column is included by default on the provisioned list.
To add a column to a list definition in a Feature
In the list definition XML, add a Field element to the Fields element.
To define the field as you want, set the attributes of the Field element.
If you make changes to a column on a list that has been provisioned, SharePoint Foundation never writes those changes back to the XML column definition itself. Instead, SharePoint Foundation stores updates made to columns as entries within the SharePoint Foundation database. For more information, see Updating Site Columns.
You can use the SharePoint Foundation object model to programmatically add columns to provisioned lists.
To add a column to a provisioned list
Use one of the following methods of the returned SPFieldCollection object to add a new column to the list: