Sharepoint - Object reference not set to an instance of an object

I got the "Object reference not set to an instance of an object" error trying to know the field value of a spListItem.

It happens that that works ok if this ListItem comes from a spList but no if it comes from a spView.

For example i added field called target and an item without value to a list and at a list field i did not get the error but it happened on a view.