datagrid, datarows

Ok, i'm picking up a project for someone else, and its confusing me very badly.

We have a datagrid, and in the footer of each column, there is a texbox. Whichever row is selected, the values of each item in that row is displayed in the txtboxes in the footer. Kinda see where I'm going? When changes are made to the columns there is another button in the footer called ADD which changes the values of the dataset if the values of the textboxes were changed.

Here's some code, it looks like a mess to me and I'm highly confused by it.

Protected Sub OnInsert(ByVal sender As Object, ByVal e As DataGridCommandEventArgs)
Dim drItem As DataRow()
Dim txtTemp As New TextBox()

drItem(0) = dsItems.Tables(0).NewRow
txtTemp = e.Item.FindControl("txtItemAdd")
drItem(1) = "test"
txtTemp = e.Item.FindControl("txtPriceAdd")
drItem(3) = txtTemp.Text
'txtTemp = e.Item.FindControl("txtQuantityAdd")
'drItem(4) = txtTemp.Text

'dsItems.Tables(0).Rows.InsertAt(drItem, 0)
'DataGrid1.DataSource = dsItems.Tables(0)
'DataGrid1.DataBind()
End Sub


PLEASE HELP! When I click the EDIT button to select the row, i get this error:
Object reference not set to an instance of an object

and it highlights the line:
drItem(0) = dsItems.Tables(0).NewRow

Can you look to see what is still Nothing? Might be dsItems?

How, and where, have you declared dsItems?