No, You cant directly store Dataset in ViewState. You can 
get XML from dataset store that Xml in ViewState. While 
getting From ViewState convert to xml and then from xml to 
dataset

yes.We can store dataset in view state.Not a dataset any 
serialible object type(datatable,dataset etc..) to be store 
in view state.

//Create new dataset :
DataSet ds = new DataSet();
//Store the dataset directly into view state
ViewState["dsn"]=ds;
//retrieve the dataset where it required
GridView1.DataSource = (DataSet)ViewState["dsn"];