What is the "BindingSource" in TableAdapter Update??

Hi,

I find the update code for TableAdapter is as follows:

Try
            me.Validate()
            me.activitybindingsource.EndEdit()
            me.activityTableAdapter.Update(me.DataSet.activity)
            MsgBox("Update successful")

        Catch ex As Exception
            MsgBox("Update failed")
        End Try

I got a gridview which is bound to the "Dataset", in which is a SQL statement selecting data from a table in SQL Server. When user modify the values in the grid, and hit the button "Update", the modified values are saved to the database.

I place the above code to the button clicked event. However, I find that "activitybindingsource" and "DataSet" got error. May I know where to declare or include them? Where do they come from??

Thanks,

Eric