Problemas con GridView

[NicroX]

Estimados tengo un problema con un GridView, al momento de actualizar este es el codigo que tengo

Cancelar

Código:

 Private Sub GridView1_RowCancelingEdit(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewCancelEditEventArgs) Handles GridView1.RowCancelingEdit
        GridView1.EditIndex = -1
        If cod_memtec.Text <> "" Then
            cargagrid("V_M....", "select * from ....., GridView1) 'esto carga la grilla
        Else
            cargagrid("V_M....", "select * from ....., GridView1)
        End If
    End Sub

Editar

Código:

    Private Sub GridView1_RowEditing(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewEditEventArgs) Handles GridView1.RowEditing
        If GridView1.SelectedIndex >= 0 Then
            GridView1.EditIndex = e.NewEditIndex
            GridView1.PageIndex = 0
            If cod.Text <> "" Then
                cargagrid("V_M....", "select * from ......, GridView1)
            Else
                cargagrid("V_M......", "select * from ......., GridView1)
            End If
        Else
            RegisterStartupScript("mensajes", mensaje("Debe seleccionar primero el registro ..."))
        End If
    End Sub

Update

Código:

If GridView1.SelectedIndex >= 0 Then
            Dim dt = CType(Session("TaskTable"), DataTable)
            Dim row = GridView1.Rows(e.RowIndex)
            Dim oDataRow As DataRow
            Dim oDataadapter As SqlDataAdapter
            Dim oDataSet As New DataSet
            Dim xDataSet As New DataSet
            Dim conectorx As New SqlConnection
            Dim conectorx2 As New SqlConnection
            conectorx.ConnectionString = sql_conexion
            Dim cod, cam As String
            Dim a As String = row.Cells(1).Text
            cam = GridView1.SelectedRow.Cells(5).Text

el problema es aca, no me reconoce la linea que esta seleccionada y no me encuentra valor GridView1.SelectedRow.Cells(5).Text

espero sus comentarios