SelectecValue

[chuchufuentes]

Creo que lo que quieres es algo como esto
primero creas botones en el GV de editar

Protected Sub GridView1_RowEditing(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewEditEventArgs) Handles GridView1.RowEditing
GridView1.EditIndex = e.NewEditIndex
FillCustomerGV()

End Sub
luego para actualizar

Protected Sub GridView1_RowUpdating(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewUpdateEventArgs) Handles GridView1.RowUpdating
Dim Usini As TextBox = DirectCast(GridView1.Rows(e.RowIndex).FindControl( "txtsinigv"), TextBox)
Dim Uitem As TextBox = DirectCast(GridView1.Rows(e.RowIndex).FindControl( "txtitemgv"), TextBox)
Dim Uparte As TextBox =


If Usini.Text <> "" Then

Ucosto.Text = Replace(Trim(Ucosto.Text), ",", ".")
Else
Ucosto.Text = "0"
End If

If Uitem.Text <> "" Then

Uventa.Text = Replace(Uventa.Text, ",", ".")
Else
Uventa.Text = "0"
End If


If Udescri.Text <> "" Then

GridView1.EditIndex = -1
FillCustomerGV()
Else
alert("Falta la Descripcion de la Parte")
End If
End Sub

para cancelar o no hacer nada

Protected Sub GridView1_RowCancelingEdit(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewCancelEditEventA rgs) Handles GridView1.RowCancelingEdit
GridView1.EditIndex = -1
FillCustomerGV()
End Sub
No se si esto es lo quieres