How can I set the Modified By, Created By, Date Modified, Date Updated fields via the MOSS object model? (without making an new version)

There are a few problems with the MOSS object model when adding new files using the SPFileCollection.Add() method. In particular, there is no overload that accepts both the "bool overwrite" parameter AND the details of the user who did the update at the same time.



Consequently, the upload of a file to a versioned list in SharePoint requires that you separately add the file with overwrite on and then update the User and Time stamps at a later stage.

Unfortuntately, the "Author" and "Editor" fields accessible via the SPFile Object are read-only. You can however take advantage of the UpdateOverwriteVersion(); available on list items to update these stamps manually. See the code below:

//The authenticating user needs to be service account as it uses database access, 
// so we must pass in current user as parameter when adding file.
SPUser updatingUser = EnsureUser(HttpContext.Current.User.Identity.Name, web);
currentFile = fileCollection.Add(newDocument.Name, contents, fileProperties, addAsNewVersionToExistingFiles);

//Get list item from SPFile object
SPListItem listItem = currentFile.Item;

//Overwrite with correct values as the object model doesn't allow us 
// to both specify overwrite=true and the specific user names.
listItem["Author"] = updatingUser;
listItem["Editor"] = updatingUser;
listItem.UpdateOverwriteVersion();