I am trying to save a dataset to a database. I got a dataset from another class, Now changes will be made on the form by a user on a datagridview, then the changed Dataset
In order to run Update method of SqlDataAdapter you must have to configure InsertCommand, DeleteCommand and UpdateCommand properties along with SelectCommand of SqlDataAdapter or construct the SqlCommandBuilder object which configure these commands implicitly.
Hey try following this tutorial here http://support.microsoft.com/kb/308507 first and then adapt it to your needs.