unable to update date data in sharepoint list

What is the general approach we follow when we try to add / edit a SPListItem using the SharePoint object model? Yes I know it! Almost everybody will have a common answer to this (which is something similar to what is provided below).

SPListItem item = SPList.Items.Add();

item["Column1"] = "value for column 1";

item["Column2"] = "value for column 2";

item.Update();

The last line in the code above "item.Update()" does the final task of updating all the assigned value for that specific item within the SPList.

But is this the only way to update an item? No, we can also update the same item using

item.SystemUpdate();

Hope you find this tips useful and of assistance.

Thanks,
Bijayani
Learn about SharePoint Migration.

This error is encountered because when trying to modify the above mentioned fields and use the listitem.Updated() property to implement the changes.

The ListItem.Update() method will affect changes to the modified or the modified by fields, thus to overcome this issue it is always advisable to use the ListItem.SystemUpdate() property to implement the changes. Basically the SystemUpdate property updateds the chages made to the list item without affecting changes to the Modified or the Modified By fields.

For more information on SystemUpdate,

http://msdn.microsoft.com/en-us/library/ms461526.aspx

http://sanketinfo.wordpress.com/2009/07/26/error-invalid-data-has-been-used-to-update-the-list-item-the-field-you-are-trying-to-update-may-be-read-only/

http://blogs.technet.com/victorbutuza/archive/2009/01/20/sharepoint-designer-2007-workflow-error-occurred-on-update-list-item-when-field-is-person-group.aspx