Sorting Gridview/Datagrid after importing from Excel

Protected Sub Gridv_Sorting(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewSortEventArgs) Handles Gridv.Sorting
        Dim sortExpression As String = e.SortExpression
        ViewState("SortExpression") = sortExpression
        If SortDirection = SortDirection.Ascending Then
            SortDirection = SortDirection.Descending
            SortGridView(sortExpression, DESCENDING)
        Else
            SortDirection = SortDirection.Ascending
            SortGridView(sortExpression, ASCENDING)
        End If
    End Sub
    Private Property SortDirection() As SortDirection
        Get
            If ViewState("sortDirection") Is Nothing Then
                ViewState("sortDirection") = SortDirection.Ascending
            End If
            Return DirectCast(ViewState("sortDirection"), SortDirection)
        End Get
        Set(ByVal value As SortDirection)
            ViewState("sortDirection") = value
        End Set
    End Property
  Private Sub SortGridView(ByVal sortExpression As String, ByVal direction As String)
        Dim con As OleDbConnection = Nothing
        Try
            con = New OleDbConnection(";Extended Properties=""Excel 8.0"";")
        Catch ex As Exception
            lt1.Text = ex.Message
            Exit Sub
        End Try
        Dim sSQL As String = "SELECT * FROM [Excel$];"
        Dim cmd As New OleDbDataAdapter(sSQL, con)
        Dim ds As New DataSet
        Try
            cmd.Fill(ds, sSQL)
            Dim dv As DataView = New DataView(ds.Tables("sSQL"))
            'UpdateColumnHeaders(Gridv)
            Gridv.DataSource = ds
            Gridv.DataBind()
            'If Not (ViewState("ssortexp").ToString() = "") Then
            '    dv.Sort = (ViewState("ssortexp").ToString() + ViewState("sorder").ToString())
            'End If
        Catch ex As Exception
            lt1.Text = ex.Message
            Exit Sub
        Finally
            con.Close()
        End Try
    End Sub
    Protected Sub Gridv_RowCreated(ByVal sender As Object, ByVal e As GridViewRowEventArgs)
        If e.Row.RowType = DataControlRowType.Header Then
            Dim sortColumnIndex As Integer = GetSortColumnIndex()
            If sortColumnIndex <> -1 Then
                AddSortImage(sortColumnIndex, e.Row)
            End If
        End If
    End Sub
    Private Function GetSortColumnIndex() As Integer
        For Each field As DataControlField In Gridv.Columns
            If field.SortExpression = DirectCast(ViewState("SortExpression"), String) Then
                Return Gridv.Columns.IndexOf(field)
            End If
        Next
        Return -1
    End Function
    Private Sub AddSortImage(ByVal columnIndex As Integer, ByVal headerRow As GridViewRow)
        ' Create the sorting image based on the sort direction.
        Dim sortImage As New Image()
        If SortDirection = SortDirection.Ascending Then
            sortImage.ImageUrl = "images/arrow.gif"
            sortImage.AlternateText = "Ascending Order"
        Else
            sortImage.ImageUrl = "images/arrowdown.gif"
            sortImage.AlternateText = "Descending Order"
        End If
        ' Add the image to the appropriate header cell.
        headerRow.Cells(columnIndex).Controls.Add(sortImage)
    End Sub