SharePoint By Gaurav Goyal

A very good article on how to maintain file version history when moving/copying files between SharePoint sites. You must read it. I has an example of code which demonstrates how to do. http://sharepointvenividivici.typepad.com/sharepoint-customization/2011/06/maintain-file-version-history-when-movingcopying-files-between-sharepoint-sites.html

Download SharePoint 2010 SDK Code Samples from Microsoft's website. Download from Microsoft

Use Recycle() Method to move your List or List Item into Recycle Bin. i.e. : spListObject.Recycle(); spListItemObject.Recycle();

A very good article on How to create a custom field in SharePoint 2010. http://www.c-sharpcorner.com/uploadfile/Roji.Joy/creating-a-custom-field-type-for-sharepoint-2010-email-validation-field/