how to delete multiple records with checkboxes in a datagrid?

hello sir,

im trying to delete multiple records with checkboxes in datagrid but im getting an error

Object reference not set to an instance of an object

at line

dgids = CType(i.FindControl("id"), Label).ToString()

here is my sample code

Dim bxschked As Boolean

Dim i As DataGridItem

Dim dgids As String = ""

For Each i In dg3.Items

Dim delchkitm As CheckBox

delchkitm = CType(i.FindControl("chkdel"), CheckBox)

If (delchkitm.Checked) Then

bxschked = True

dgids = CType(i.Cells(0).FindControl("id"), Label).ToString()

End If

plz help me out ,im new to asp.net

thanks in advance

hemant