dataset Updating

I have a dataset (below) and I need to go through all the rows setting one of the fields (defulat to 0). I'm trying to do a count of the rows then a for next but am not sure how to update the dataset:


OleDbDataAdapter1.Fill(DsCurrentUserList1, "table")
Dim objTable As DataTable
Dim drRows As DataRowCollection
Dim objNewRow As DataRow
objTable = DsCurrentUserList1.Tables("table")
drRows = objTable.Rows

Dim iCnt As Integer
Dim n As Integer

iCnt = DsCurrentUserList1.Tables("table").Rows.Count

If cmbDefaultChoice.Text = "Yes" Then
TxtDefault.Text = 1
'reset the other rows
objNewRow("Default") = 0
For n = 1 To iCnt
'update default value to 0for each row
Next


Thanks Again,

John