To return the collection of items for a list or document library, use the Items property or one of the GetItems methods of the SPList class, or use the Items property or GetItemsInFolder method of the SPDocumentLibrary class. To create an item, use one of the Add methods.
Use an indexer to return a single list item from the collection. For example, assuming the collection is assigned to a variable named collListItems, use collListItems[index] in C#, or collListItems(index) in Visual Basic 2005, where index is either the index number of the item in the collection or the display name of a list field.
Always use a Get* method on a higher-level SharePoint object to return specific items or files. If you use one of these methods, you are not required to enumerate all the items in the list or library. For example, instead of using the SPListItemCollection object, use the GetFile method of the SPWeb class to return a specific file from a library in a Web site, or use the GetItems method of the SPList class, and pass an SPQuery object to return specific items from a list.