c# - TableAdapter error - namespace not found -

i trying insert data database through dataset. database table called users , dataset called userdataset. getting error says

the type or namespace name 'userdataset' not found (are missing using directive or assembly reference?)    

also connecting datasets in correct way, not sure how check if connection correct.

i using this msdn reference.

usertableadapters.userstableadapter = new usertableadapters.userstableadapter();     user.usersdatatable usertable = us.getdata();      userdataset.usersrow newusersrow;     newusersrow = userdataset.users.newusersrow();    newusersrow.username = textbox1.text;     newusersrow.password = textbox2.text;      this.userdataset.users.rows.add(newusersrow);      this.userstableadapter.update(this.userdataset.users);