Version History in SharePoint 2010

I have List with 40+ fields in List and items are creating/updating with non-SharePoint UI. When there is an update to list item, we just updating all the fields to SPListItem and calling item.Update().

Now customer requirement is to have field level tracking so that on every update, system should be intelligent to identify the only modified fields in list item.

Any idea on getting the summary开发者_StackOverflow中文版 of changes on each update?

I prefer to do this SharePoint object model

Have a look at the SPListItem.Versions property. From there, you can get access to SPListItemVersion objects that correspond to individual versions. This class provides you access to previous values of the item's fields.